Home » General Incubation Info

1.General Tips About Egg Incubation
2. Waterfowl Considerations
3. Incubating with Surehatch Incubators
4. Incubation Facilities
5. Temperature
6. Weight Loss During Incubation
7. Turning
8. Ventilation
9. Monitoring Development
10. Hatching Facilities
11. Keeping Records
12. Incubation and Embryology FAQ's
13. Poultry Industry and Production Questions
14. Breeds of Chickens
15. Egg Grading and Candling
16. Incubating Your Eggs
17. FAQ's on Candling

General Tips About Egg Incubation

• Correct incubation conditions are important for development and hatching of eggs. The required conditions vary considerably between species, and some species appear more exacting in their requirements than others. Minor deviations in correct temperature may lead to a slightly shortened or lengthened incubation period, while greater variation may cause failure to develop or hatch, or result in weak chicks. Incorrect incubation conditions have also been implicated in some developmental problems of neonatal birds.

• In general, correct incubation conditions are most crucial early in incubation, with small variations being tolerated better by the embryo later in development. For this reason, eggs are sometimes left with the parents initially for seven to ten days until they have been "set" and transferred to an artificial incubator after this most crucial period, in the hope that the birds will then lay again. Alternatively, eggs are placed under a broody initially, before being placed in an artificial incubator. Both procedures may improve hatching success compared to complete artificial incubation.

• Egg cleanliness is of vital importance; it has been shown that poor hygiene and dirty eggs may significantly reduce the percentage of eggs hatching successfully. It is important that the laying sites are clean as well as conditions following egg collection. Eggs cool down once laid, therefore the contents shrink and air is drawn into the egg: bacteria may be drawn in at the same time. Invasion of bacteria such as Staphylococcus spp., Salmonella spp. and Escherichia coli may lead to death of embryos or neonates. Eggs may be cleaner if they are collected immediately after laying rather than after they have been "set".

• Eggs which are deformed should not be incubated.

• Eggs which are noted to be cracked at the time of collection are generally discarded, and grossly contaminated eggs may also be discarded at this time. If such eggs are particularly valuable, they should be separated from other eggs for incubation, due to the greater risk of infection.

• Eggs which become cracked during incubation may be repaired, if the crack is small, with e.g. surgical grade cyanoacrylate glue, candle wax dripped onto the crack, nail varnish, correction fluid or sticky tape (it has been suggested that products containing acetone should be avoided, due to possible toxicity . Eggs which are cracked should be incubated in an incubator (not under parent or broody), with extra care taken in their handling and monitoring. It is important to ensure that the material used to cover the crack is applied to the minimum surface of the shell required to seal the crack. A thin layer of bone cement may be applied over a crushed area of shell and a hole in the shell may be repaired by gluing an appropriate piece if sterilized shell, parafilm, tissue or gauze over the defect. Care should be taken to avoid sealing over larger areas of the shell than absolutely necessary as this prevents necessary gaseous exchange.

• If the shell membranes have been penetrated the egg is likely to have become contaminated with pathogens and the yolk, embryo or blood vessels may have been physically damaged. Hatchability is greatly reduced.

• A pipped egg which is being parent or broody incubated and becomes damaged should be moved to a hatching incubator.

•  Records: Accurate and detailed records are very important in incubation. All eggs should be individually identified and details recorded including the identity of the parents, and details of their pedigree, nutrition and breeding and incubation behaviour, initial weight, date of setting, details of incubation such as results of candling, incubator used, weight loss (if this is being monitored) expected and actual hatching dates, as well as evaluation of the hatched chick or results of investigation into eggs which fail to hatch.

•  Parent incubation generally provides the ideal conditions of temperature and humidity for development and hatching. However, not all species or individuals are equally good sitters, particularly in captive situations, in which birds may be disturbed and not feel secure. Additionally, small species in particular are vulnerable to predation while sitting, especially if nesting in an open site. Also, normal incubation behaviour may not be suitable for birds being maintained in an environment very different from their native habitat.

• If allowed to sit, hatch and rear their chicks, most birds will produce only one clutch a year, whereas two, three or even more clutches of eggs may be produced if the eggs are removed.

• It may be less easy to monitor parent-sat eggs for fertility and continued development, with an attendant risk of disturbing the birds.

• In captive conditions it may be more likely that nesting materials will not be fresh and clean, but contaminated with droppings, or include mouldy vegetation.

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Waterfowl Consideration

• As with other birds, parent incubation should provide the optimum conditions for the developing embryos.

• In mixed-species enclosures there may be competition for nest sites and also dumping of eggs by some birds into the nests of other birds. In general, a pair of waterfowl occupying their own pen are less likely to be disturbed by other birds and more likely to sit successfully.

• Both predation (of eggs and of the sitting female) and disturbance may be major problems, particularly for birds that have chosen sites which cannot be described as ideal.

• Swans and geese frequently are good at sitting their own eggs, and ducks may also sit tightly if not disturbed excessively. Swans and many geese are commonly left to sit their own eggs, and to rear the young. Their larger size, well-defined territories and continuing strong pair bond reduces the chance of losses from predation of eggs.

• With species such as the Cape Barren goose (Cereopsis novaehollandiae - Cape Barren goose), which lay their eggs during the winter, consideration must be given to the practicalities of incubation in winter conditions and the additional stress placed on the birds, unless they are in sheltered winter accommodation.

• Most species of waterfowl can be stimulated to lay a second clutch of eggs if the first clutch is removed. However, females commonly change their nesting site due to the "predation" of the eggs and may stop laying if eggs are removed from all nesting sites. It may be advantageous to allow birds to sit and hatch eggs of their own or another more common species after a second clutch has been laid.

• Birds which are sitting may leave the nest for only a short time each day. In species in which only one parent incubates the bird may lose a considerable amount of weight over the period of incubation and it is important to ensure that food is freely available at whatever time the bird leaves the nest to feed.

• Waterfowl species vary in their response to disturbance at the nest site. Some are quite tolerant but others will desert the nest if subject to any disturbance. This makes regular inspection of the eggs for fertility and development difficult.

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Incubating using a Surehatch Incubator

• Artificial incubation is commonly used in aviculture. Eggs incubated in this way are safe from predation and are not at risk of being deserted by the bird sitting on them, for example due to disturbance. Eggs in incubators are at risk if the power supply to the incubator fails, for example if there is an electrical power cut.

• Artificial incubation allows many more eggs to be incubated than parent incubation and with less effort than maintaining broodies. However, very precise control and attention to the progress of individual eggs is required for the best results.

• Accurate control of temperature and humidity are vitally important in artificial incubation. Cleanliness is also very important; the ease with which an incubator may be cleaned and disinfected is an important consideration when choosing an incubator.

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Incubation Facilities

• The area in which incubators are kept should be easily cleaned and well ventilated, and should also be maintained at a constant temperature.

• Most modern incubators are electric, although paraffin and gas powered incubators do still exist. Incubators vary greatly in size, may be still air (in which air moves by convection) or forced air (in which air is moved using a fan) and may or may not include automatic egg turning.

• All incubators also require added water to maintain the correct humidity. This is usually provided in the form of one or more water trays.

• Still air incubators, which have a temperature gradient from the top (higher temperature) to the bottom of the incubator may approximate the natural conditions in a nest (in which the incubating parent is providing heat from above), but they may easily be overloaded and the eggs then poorly ventilated. Forced air incubators have a much more uniform temperature throughout, and better ventilation, and may be used for many more eggs.

• N.B. Individual preference plays a large part in choosing an incubator. In general, better results are likely to be obtained if the operator is familiar with, and comfortable using, the incubator.

• Incubators should be cleaned and disinfected (and fumigated if required - see before the breeding season. A disinfectant suitable for incubators should be chosen and care is needed in cleaning the Once clean, they should be set up without any eggs and switched on.

• After the incubator has warmed up and appears to be at the correct operating temperature, it may be tested by incubating some bantam eggs. The temperature should be monitored and recorded several times daily, but adjusted on the basis of average daily readings rather than by micro-correction every few hours.

• Wet-bulb readings should also be monitored to indicate humidity levels. A pattern of a slight rise in readings on the wet-bulb thermometer may indicate a soiled wick and this should be changed

• For ideal results, all the eggs inside one incubator should be of the same age (stage of incubation) and size. In practice, eggs of different sizes and ages are commonly incubated in the same machine.

• Eggs close to the end of incubation produce a considerable amount of heat and therefore contribute locally to the air temperature, particularly in a still-air incubator.

• Large late-incubation eggs should not be placed near to small, newly-set eggs as they may affect their incubation temperature.

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Temperature

• Incubators are most reliable if kept in a room with a constant temperature. Maintaining a steady incubator temperature inside a room which varies widely in temperature is practically impossible.

• The temperature inside an incubator should be measured with a thermometer. This may be either a traditional mercury thermometer or an electronic thermometer. The bulb of the thermometer may be placed inside a blob of Plasticine or similar to reduce changes in readings due to minor fluctuations and give an average reading. It is important to make sure that the readings on the thermometer are accurate or, if there is an error, that the error is known, stable and can be corrected for. New thermometers should be checked against one known to be accurate. Either traditional mercury thermometers or digital thermometers may be used.

• Even in a forced air incubator there will be differences in temperature within an incubator, which may be mapped by placing thermometers in different places within the incubator. In a still air incubator the temperature varies vertically within the incubator and there may be a difference of several degrees between the bottom and the top of the incubator. The temperature should be kept at that required by the eggs at the level at which the eggs are kept. In order to monitor this, a thermometer should be placed at the same level as the eggs.

• N.B. the temperature will fall when the door is opened to add, remove or manipulate eggs. These procedures should be carried out quickly but carefully.

• For normal development, eggs must be maintained within a narrow temperature range. Both too high and too low temperatures may be deleterious to eggs, although in general eggs are more tolerant of low than high temperatures:

  • A temperature which is too high by a few degrees may be lethal and even a rise of just 1.0-1.5C (2-3F) may cause embryo death after perhaps four or five days.

  • Temporary cooling (as may occur naturally when an incubating bird leaves the nest to eat etc.) does not appear to be deleterious.

  • Constantly slightly low temperatures may result in slow development and late hatching, but if the temperature is maintained at a sufficiently low level, deaths may result.

  • Incorrect temperatures also affect incubation time, with earlier hatching if the temperature has been slightly high, later hatching if the temperature has been slightly low.

• Humidity levels can be measured with a wet-bulb thermometer.

• A wet-bulb thermometer is an ordinary thermometer in which the bulb is kept damp by means of a "wick" of covering the bulb and dipped into a small container of water. Evaporation from the wick reduces the temperature of the thermometer bulb.

• Since evaporation is greater in a drier environment, a lower temperature reading indicates a lower humidity and a higher temperature reading indicates a higher humidity. A dirty wick gives a falsely high reading. The distance from the thermometer to the water reservoir for the wick should be about one inch (2.5cm).

• Relative humidity is proportional to the wet bulb reading if the dry bulb reading is constant. Tables indicating relative humidity for different wet bulb readings at different dry bulb temperatures are available in some incubation texts .

• All incubators contain some method of maintaining humidity. Humidity is usually manipulated by changing the surface area of water trays placed in the bottom of the incubator - a larger surface area will produce a higher humidity. For example, trays may have a sloping floor, in which case increasing the depth of water will increase the surface area. Alternatively, surface area may be increased by placing sponges into the water with part of their surface coming out of the water.

• N.B. humidity will drop when the incubator is opened and , particularly in a still air incubator, may take some time to return to the previous level. Spraying the floor of the incubator lightly with water before closing the incubator door may be used to increase the rate at which humidity is restored.

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Weight loss during incubation

• Eggs normally lose a total of 18% of their weight during incubation, due to loss of water vapour which diffuses across the egg shell . Eggs should lose 15% of their weight from the start of incubation to the start of hatching (internal pipping). Monitoring and if necessary manipulation of their weight loss may be used to improve hatching success.

• For ideal results, each egg should be weighed individually on an accurate balance and the actual weight loss plotted on a graph and compared with the ideal weight loss for that egg. This may be done by hand or using an appropriate computer programme.

• Weight loss may be too fast due to thin shells or low incubator humidity. Weight loss may be too slow due to thick shells or high incubator humidity.

• If weight loss is too fast or too slow, it may be manipulated. N.B. Correcting the rate of weight loss after the first third of incubation is much more difficult.

• The correct rate of weight loss early in incubation appears particularly important for hatchability; incorrect early rates of weight loss may be fatal to the embryo despite later correction giving the required overall weight loss.

• If several incubators are kept at slightly different relative humidities, an egg may be moved into an incubator at higher humidity if it is losing weight too fast, or lower humidity if it is not losing weight sufficiently fast. Other methods involve altering the porosity of the egg shell:

  • Porosity (and therefore water loss) may be increased by careful thinning of the eggshell using sandpaper.

  • Conversely, part of the eggshell may be painted over with nail varnish to decrease water loss through the shell.

  • In extreme cases of excessive weight loss, rehydration may be used. This involves completely submerging the egg in cold (approximately 10°C, 50°F) sterile water for up to five minutes daily or even more frequently, with accurate weighing to monitor the uptake of water during the procedure. The cold temperature causes the egg contents to contract, drawing water into the egg. The frequency and duration of dipping should be varied according to the degree of weight loss and the stage of incubation. Care must be taken not to over stress the embryo by dipping for too long. Dipping in antibiotic solution has been described for the first dip (3mg tylosine tartrate (Tylan Soluble, Elanco Animal Health) in 1 litre sterile 09% saline giving 3000 parts per million tylosin solution). N.B. in general, eggs which are normally incubated in very damp conditions are likely to require a higher level of humidity during incubation than eggs which would be incubated in the wild in very dry conditions.

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Turning

• Either automatic or hand turning may be used.

• If eggs are turned by hand they should be turned several times per day (minimum five times daily), and always turned an odd number of times so that the egg is on opposite sides for the longest internal  (overnight) on alternate nights.

• Eggs should be marked with "O" on one side and "X" on the opposite side, and all turned so that the "O" is uppermost on all the eggs after one turning and the "X" is uppermost after the following turning.

• Eggs should be turned in one direction one day and the other direction the following day (i.e. rotated along their long axis clockwise and anticlockwise alternately). Continual rotation in the same direction may lead to problems such as twisting of the chalazae, rupture of the yolk sac or rupture of blood vessels in the embryo.

• Various means of automatic turning may be used. Eggs may be laid on their sides on rollers which move one way then the other alternately, or on a flat tray with movement provided by the movement of rods one way then the other (or the rods may stay still while the tray moves). An alternate method involves eggs being placed small end downwards in trays which are tilted to 45 degrees one way then 45 degrees the other way.

• N.B. if automatic turning is used, monitoring is required at different times of day to confirm that the eggs are being turned.

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Ventilation

• Developing embryos require a flow of air to provide oxygen for respiration and to remove carbon dioxide.

• Rigid egg trays with an open mesh construction should be used to allow air to flow around the eggs and the addition of extra obstructions to air flow should be avoided.

• N.B. Air flow is lower in still air than in forced-air incubators and it is important not to overcrowd the eggs.

• The movement of air in an incubator containing eggs will be different from in the same incubator when empty, which is one reason why the incubator function should be checked with bantam eggs.

• Temperatures within the incubator may fluctuate if air flow is obstructed. If this cannot be rectified it is important to place eggs only in the most stable temperature areas of the incubator.

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Monitoring development

• The development of the embryo within the egg is monitored most commonly by means of candling - shining a bright light through the egg. Candling is difficult if eggs have a very thick or patterned shell.

• Eggs may also be tested by Egg Floatation. The egg is placed in a bowl or bucket of water. Fresh eggs will sink, late-incubation eggs will float and live eggs close to incubation can be seen to move.

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Hatching Facilities

• A higher humidity is required for hatching and a separate incubator should be maintained for this purpose. High humidity is very important to avoid the shell membranes drying out, sticking to the chick and being unable to turn properly and push its way out of the shell. Either a still air or a moving air incubator may be used as a hatcher. N.B. frequent opening of the incubator , by lowering humidity, may result in hatching problems. A hatcher with a clear top or panel is useful to allow monitoring of hatching without constant opening of the hatcher.

• Hatchers tend to get dirty rapidly with bits of fluff, shell, etc. Frequent cleaning and sterilization is recommended, preferably after the hatching of each chick or batch of chicks. If chicks are hatching daily, two hatchers may be used, so that eggs may be in one hatcher while the other is being fumigated. If fumigation is not used, hatchers may be disinfected with a disinfectant of suitable efficacy and safety for use with eggs.

• Chicks may be hatched inside individual plastic boxes within the hatcher. This will reduce contamination of the hatcher with fluff, bits of eggshell etc. and also allows easy monitoring of which chick has hatched from which egg.

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Keeping Records

• Accurate and detailed records are very important in incubation.

• In addition to records of individual eggs (see above: Introduction and General Information) it is important to keep records of the temperature (dry bulb) and the humidity (from wet bulb) of each incubator, so that increases or decreases in temperature or humidity are detected early and can be corrected.

• Trends in temperature and humidity may be most easily seen if plotted on a graph.

• Waterfowl eggs vary considerably in size (e.g. 25 grams for a teal egg, versus around 300g for a swan egg) and in the normal environmental and climatic conditions under which they would be incubated. Correctly controlling incubator conditions (temperature and humidity) for all the different eggs may be challenging .

• Hatching success may be improved by using parent or broody incubation for the first ten days. Conditions in the early stages of incubation are more critical than late in incubation.

• For waterfowl eggs, incubated at 99.5°F dry bulb temperature, with a wet bulb reading of 84°F, giving 55% relative humidity is suggested as a starting level .

• Incubation conditions for waterfowl eggs of 37.9°C (99.0°F) dry bulb temperature and 31.1°C (88°F) wet bulb temperature, with a hatcher at 36.9°C (98.4°F) dry bulb, 31.1-32.2°C (88-90°F) wet bulb have been suggested .

• A separate hatching incubator should be used with a high (90%-100%) relative humidity, preventing the eggshell membranes from drying. Downies should be left in the hatcher until they are dry.

• Hatching may need to be assisted, with care, checking the blood has been absorbed from the membranes and that the yolk has been absorbed, and keeping the membranes damp at all stages

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1. Incubation and Embryology FAQ's

Poultry Industry and Production Questions:

2. Why do brown shelled eggs cost more than white shelled eggs?

Brown shelled eggs cost more because the chickens that produce these eggs eat more feed and production costs are more.

3. Why are brown shelled eggs bigger than white shelled eggs?

Brown shelled eggs are bigger than white shelled eggs because they are produced from a dual purpose breed (eggs - meat) that is larger in size (6-7 lbs.) than a Leghorn breed that is smaller in size (3-4 lbs).

4. Does the time of the year affect the fertility rate?

Extreme cold (winter) or extreme heat (summer) can lower fertility rate dramatically.

5. How many females can one male service?

One male egg producing chicken (Leghorn) can service 10 - 15 females. One male dual purpose chicken (Rhode Island Red) can service 6-8 females.

6. What is the average life of the male chicken?

A male chicken would live on the average of 3-5 years.

7. How large are female chickens?

A female White Leghorn is about 4 lbs. and a female Rhode Island Red is about 6-7 lbs.

8. How can you tell a hen from a rooster?

Difficult to tell at hatch unless they are feathersexed (female primary feathers are longer at 3-4 days of age). In adults, males are larger with longer wattles and larger combs.

9. Do you need sunlight to formulate hard shells on eggs?

No. An adequate source of calcium in the diet is needed.

10. Do chicken houses need to be heated?

No. Usually chickens in large commercial houses provide their own heat.

11. How much light is needed in the chicken house?

Only enough light is needed to read a newspaper at arms length (about 1 foot candle).

12. When does production begin?

At sexual maturity. This is about 17-18 weeks of age for the female hen.

13. What factors affect egg production?

Many factors affect egg production. The most important are diet (nutrition), temperature, humidity, length of artificial light (14 hours of constant light is recommended), and other nutritional and environmental factors.

14. How long does it take to raise a fryer?

About 42-49 days; six to seven weeks to market weight of 4.5 lbs.

15. What is a blood spot?

A blood spot occurs from a broken blood vessel across the stigma line on the yolk follicle when the yolk is released into the reproductive tract.

16. What is a meat spot?

A meat spot occurs when a part of the oviduct peels off when the egg is formed.

17. Is there one kind of egg carton that is better than another?

A styrofoam carton is preferred to a paper carton because it protects the eggs better.

18. How long does it take to put the shell on the egg?

It takes about 20-22 hours for the shell to be deposited around the yolk and albumen. This occurs in the uterus or shell gland.

19. What is salmonella?

Salmonella is a bacteria that can form on the outside of the shell when an egg or its contents become contaminated. It can cause food poisoning if eggs are not properly handled and cooked.

20. What are the critical issues related to salmonella?

Eggs and other food should be properly handled and cooked. Salmonella poisoning is not a problem if food products are properly prepared.

21. How often are eggs infected with salmonella?

It has been shown that possibly one egg in one million eggs produced may have some salmonella growing inside an intact egg.

22. What is the proper way to cook an egg?

Eggs can be cooked in many different ways. Thoroughly cooked eggs include: eggs cooked until the whites and yolks are not runny, hard-cooked eggs, baked eggs, and other egg-rich foods cooked to an internal temperature of at least 106 degrees F.

23. Do brown eggs have more cholesterol than white eggs?

Brown and white shelled eggs have the same amount of cholesterol (200-210 mg per egg).

24. How many eggs does a chicken lay per year?

250-270 eggs per year.

25. What causes a double yolk egg?

The release (ovulation) of two yolks from the ovary simultaneously. It is abnormal and does not occur very often, but will occur in a hen's egg production cycle.

26. Is the shell hard or soft when laid?

The egg is hard when laid by the hen.

27. How is the egg fertilized?

When the rooster inseminates the hen, the male sperm swim up the reproductive tract and localize in sperm host glands in the infundibulum. When a yolk is released one sperm penetrates the germmal disc and fertilization has begun.

28. When do the chicks need water?

Immediately. The chicks need to drink water when they are transferred to the brooder box.

29. When do they need food?

The chick needs food probably the first day, but can survive for up to 3 days after hatching.

30. What are hackle feathers?

Hackle feathers are neck feathers on a chicken. A rooster has long pointed ones, and the female has short rounded ones.

31. What are saddle feathers?

Saddle feathers are feathers toward the tail end of the chicken. A rooster has long pointed ones, and the female has short rounded ones.

32. Can you tell the sex of the chicken from the feathers alone?

Yes, if the breed is feathersexed. The female chicks' primary feathers will be longer than the males. It is difficult to tell the sex of a newly hatched chick if the breed does not have the feathersexed characteristic.

33. Is there a pecking order?

Yes, within a group of chickens from two to hundreds they establish a pecking order of dominance.

Breeds of Chickens

33. Why are brown shelled eggs bigger than white shelled eggs?

Brown shelled eggs are bigger than white shelled eggs because they are produced from a dual purpose breed (egg-meat) that is larger in size (6-7 lbs.) than a Leghorn breed that is smaller in size (3-4 lbs).

34. How do you know what color shell the eggs will have?

The earlobes of the chicken dictate the color of the shell (white ear lobes = white eggs; red earlobes = brown eggs).

35. What kind of chicken lays green eggs?

An Aracona chicken lays green shelled eggs.

Egg Grading and Candling

36. What is the weight of jumbo, extra large, large, medium, small and pee wee eggs?

Jumbo - 30 ounces per dozen
Extra Large - 27 ounces per dozen
Large - 24 ounces per dozen
Medium - 21 ounces per dozen
Small - 18 ounces per dozen
Pee Wee - 15 ounces per dozen

37. What are the egg grades?

Egg grades are:

• AA - shell-clean, air cell-1/8" or less in depth, white-clear and firm;

• A-shell-clean, air cell 3/16" in depth, white-clear; and

• B-shell-clean to slightly stained, air cell over 3/16" deep, white-weaker and watery.

38. What is a leaker?

A leaker is a broken egg where the contents leak out of the shell.

39. What is candling?

Candling is shining a bright light near the egg to determine the egg quality and also embryonic development.

40. When should the eggs be candled?

Eggs can be candled anytime after about Day 5 of incubation through Day 17.

41. How many eggs should be candled at a time?

Out of 2 dozen eggs in the incubator, probably no more than 5-7 eggs should be candled at one setting.

42. How long should the eggs be out of the incubator?

No more than 5 to 10 minutes at a time.

Incubation

43. What is the best temperature for storing eggs?

Egg should be stored between 55 and 60 degrees F.

44. How much humidity is needed?

Enough humidity is needed to maintain a wet bulb temperature of about 85 to 87 degrees F (50-55 percent relative humidity). This is normally attained if water channels in incubator are kept full.

45. How do you disinfect the incubator?

Disinfect incubator with 10 percent bleach solution, then wash with warm soapy water and rinse thoroughly.

46. Does when the egg was laid affect the hatch date?

No. If fertile eggs are stored properly (55-60 degrees F) then hatch date for the chicken will be about 21 days following the time they are placed in the incubator.

47. When should the incubator be prepared for the eggs?

About one week before starting the incubation process.

48. Where should the eggs be stored, if they cannot be set right away?

If they cannot be put in an incubator right away, then they should be kept in a cool room at a temperature of 55-60 degrees F.

49. What is the longest eggs should be held before incubating?

No more than seven days.

50. What is the correct temperature for incubating fertile eggs in a still air incubator?

Optimum temperature is 100.5 degrees F.

51. What is the temperature range that is acceptable during incubation?

Temperature range is 99 -103 degrees F.

52. What is the lowest temperature?

Lowest temperature should be 99 degrees F.

53. What is the highest temperature?

Highest temperature should be 103 degrees F. Never keep at 103 degrees F for more than than a few hours.

54. How do you check the accuracy of the incubator thermometer?

Accuracy of an incubator thermometer can be checked by placing a medical thermometer and an incubator thermometer in a pan of 100 degree F water, or take a good thermometer from the science storeroom and place it next to the incubator thermometer in the incubator at 100 degree F.

55. When should the plugs be removed from the incubator?

Remove plugs (air holes) from the top of the incubator when you see the chicks start to hatch.

56. What are the factors for success?

• Successful hatches can be obtained by:

• Securing fertile eggs

• Maintaining the correct temperature

• Maintaining correct humidity levels

• Increasing ventilation when chicks hatch

• Turning the eggs properly

57. What should be used to mark the eggs?

A lead pencil only.

58. Do I need to take the eggs home for the weekends?

Yes, it is encouraged to take eggs home on the first two weekends to turn the eggs and regulate temperature.

59. How do I transport the incubated eggs from school to home and back?

Carefully. Put the eggs in a styrofoam egg carton and wrap the carton in a blanket; or leave eggs in the incubator and place a blanket over them so they won't roll around.

60. Where should the eggs be placed in the car when taking them home?

Place the eggs on the front floor on the passenger side and turn on the heat.

61. What is the normal hatch time for a fertile incubated egg?

Normal hatch time for chicken eggs is 21 days.

62. What will delay the hatch?

Too low of an average temperature will delay the hatch.

63. Why are the chicks sometimes very wet and mushy?

Chicks are wet and mushy if too much humidity is in the incubator. To lower humidity at the end do not place more than one sponge in bottom of incubator.

64. How can I be sure that I have enough humidity?

If the proper water level is maintained in the bottom of the incubator the correct humidity should be maintained.

65. How can I tell if I have too much humidity?

If there is a lot of condensation on the inside of the incubator windows, then there is probably too much moisture in it. This is usually not a big problem.

66. How long should I leave the eggs in the incubator if they do not hatch on the twenty-first day?

Leave the unhatched eggs until the 23rd or 24th day.

67. What causes deformed legs?

Deformed legs are caused by poor nutrition of the hen. Other factors are disease, contamination and improper temperature.

68. How do I add water?

Add warm water (100 degrees F) with a squeeze bottle, or meat baster; do not get eggs wet.

69. How do I count the days?

Count the days of incubation from the first day the eggs are placed in the incubator. If placed in the a.m. that day would be Day 1; if placed in the p.m. that day would be Day 0, the next day would be Day 1.

70. When do I stop turning the eggs?

Stop turning the eggs on Day 18.

71. When should I put the crinoline on the wire grate?

Put the crinoline (cheese cloth) on the wire grate of the incubator after Day 17 or on Day 18.

72. How can I add additional humidity?

Add additional humidity on Day 18 by placing 2-3 wet sponges on the bottom of the incubator.

73. What should I do if the chicks do not fluff up?

If chicks do not fluff up remove sponges from the incubator and water from the channels.

74. What is the brooder box?

A brooder box is a temporary home for baby chicks up to one week of age. It contains 2-3 inches of litter, a feeder, and water. It also includes a heat source suspended above the box.

75. How do I make a brooder box?

Take a cardboard box (2' x 3' x 1') and place items mentioned in answer 74.

76. What should be used in the bottom of the brooder box?

Use soft pine-wood shavings, untreated cat litter, sand, rice hulls, or ground corn cobs, but not newspaper.

77. Do the teachers need to teach the chicks to drink and eat?

Yes, it would be a good idea to dip the baby chick's beak in the feed and water so they know where it is.

78. Should you help a chick out of the shell?

No, if the chick can not come out of the shell on its own then it is a weak chick and probably would not survive.

79. Where should the thermometer be placed in the incubator?

On the wire grate away from the heat source and in the center of the incubator.

80. What is the function of the air cell?

The air cell function is to provide the chick with air when it first starts to break open the shell.

81. What is the critical period in hatching?

The first 3-5 days and Days 18 and 19. When the embryo is forming early on and when it gets in position to hatch.

82. How often should the eggs be turned?

Eggs should be turned at least three times a day.

83. What happens if the eggs are not turned?

If eggs are not turned, the embryo will die about Day 11.

84. What causes the embryo to develop fully, but not pip the shell or hatch?

Too low or too high temperature, to too low or too high humidity.

85. Do you need to do anything to prevent the chicks from drowning?

Place marbles or rock in the water pan in the brooder box to keep chicks from drowning.

86. Why do chicks stick to the shell?

Too low humidity during incubation.

87. What causes the navel to be sore?

Too high temperature during incubation, excessive humidity near the end of incubation, or infected embryo early in incubation.

88. What should you do if the chicks pick at one another?

Separate them from each other in the brooder box, or construct another brooder box and separate the chicks.

89. Can chicks be marked?

Yes.

90. How do you color embryos?

To color embryos you inject a colored dye about .2 to .5 milliliters into the egg with a hypodermic needle near the bottom of the egg.

Embryology

91. How do you preserve embryos? Using formalin or glycerine and ethyl alcohol?

Embryos can be successfully preserved by storing them in an alcohol solution (3-4 drops of glycerine on embryo), then immerse in 70 percent alcohol (14 parts of 95 percent ethyl alcohol to 5 parts of water).

92. What is the correct procedure for breaking out an embryo?

Break open the shell on the large end of the egg, then pour out the liquid contents and carefully drop the embryo on a pie tin.

93. How long does it take to pip the shell completely?

Two to four hours.

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2. Incubating Your Eggs

1. How must I store eggs?

Your eggs need to settle for at least 24 hours if they came through the post. This allows the air cell inside the egg to return to it's normal size. Eggs should always be stored with the pointy end down while they are "in the hold". It's a good practice to follow and it will help your hatch!

If you receive eggs that are getting old, you may only let them settle overnight.

2. When is my incubator ready to start incubating?

By the time you have gotten your eggs your incubator should have been running at least 24 hours. A week is even better. This gives you time to learn what's going to happen in your incubator and allows you to make any necessary adjustments before setting your eggs. A surefire way to ruin hatching eggs is to put them in the incubator without having it properly adjusted.

Take note of the term "internal" temperature. Don't confuse internal egg temperature with internal incubator temperature. The temperature in an incubator changes constantly, rising and lowering. The temperature inside the egg will be an average of this temperature swing in your incubator.

3. What must the temperature and humidity be inside my incubator?

This is plain and simple, yet the MOST important part of hatching.

Fan Forced incubator: 37.5 degrees C measured anywhere in the incubator.

Humidity: 55% for the first 18 days, 60-65% for the last 3 days in the hatcher.

4. Is my thermometer accurate?

Thermometers go bad. Keeping the temperature accurate can be a struggle, even with very good thermometers. A nice part about running a big incubator over an extended period is that you can tweak the temperature regardless of what thermometers tell you.

After the first hatch, you can raise or lower the temperature by what the hatch tells you. If they hatched early the temperature needs to be lowered. If they hatch late the temperature needs to be raised.

You can check your Thermometer this way. Keep notes on everything you do during the incubation period. As you learn you'll have these notes to look back on. They will be the most valuable tool that you can have. It won't be long until you can say "I know what happened, all I need to do is change this one little thing". Soon you will be able to make adjustments by knowing what to do, instead of guessing!!!

5. How do I check humidity?

Humidity is checked by way of a hygrometer (wet-bulb thermometer) in conjunction with a regular "dry-bulb" thermometer. A hygrometer is simply a thermometer with a piece of wick attached to the bulb. The wick hangs in water to keep the bulb wet (hence the name "wet-bulb thermometer"). When you read the temperature on the thermometer and hygrometer, you must then compare the readings to a chart to translate from wet-bulb/dry-bulb reading to "percentage humidity".

From the relative humidity table, you can see.....

60% humidity reads about 30.5 degrees C on a wet-bulb at 37.5degrees C.

60% humidity reads about 31.6degrees C on a wet-bulb at 38.6degrees C.

80% humidity reads about 33.8degrees C on a wet-bulb at 37.5degrees C.

80% humidity reads about 35degrees C on a wet-bulb at 38.6degrees C.

Getting your humidity to become as accurate as your temperature is nearly impossible. It is almost completely impossible with a small incubator. Try to get your humidity as close as you can, and you'll be fine. Just being aware that humidity is important, and trying to get the numbers to come in close will be a huge help to your hatch.

If you can hold within 10-15% things should turn out fine.

Temperature on the other hand, is CRITICAL!!!!! I hate to beat this point to death, but a small deviation in temperature (even a couple degrees) can and will ruin a hatch. Or, at least turn a potentially great hatch into a lousy one.

6. An important point about incubator humidity

As seasons change, so goes humidity. When you are incubating eggs in January and February it will be very difficult to maintain a humidity that is as high as you like. That's because the outside humidity is so low.( Depending on where you live). By the same token, when you are incubating in June and July the outside humidity is usually much greater and the humidity in your incubator will most likely get much higher than you would like. Hatching problems will change as the season progresses. If you are doing things the same way in July as you were in January, you have to expect different results. All I am trying to say here is that your incubator humidity changes directly according to the outside humidity. Low outside, low in the incubator. High outside, high in the incubator. To adjust for these problems, you need to change the surface area of water in your incubator.

7. What is surface area?

Surface area is "the amount of surface of water exposed to air in your incubator". The depth of water has absolutely no bearing on the humidity in the incubator (unless the depth is zero). If the humidity is too low in your incubator, add surface area. Place another pan of water in the incubator, or some small, wet sponges. This will help. To decrease the humidity, remove surface area. Use smaller containers of water, or undo some of the things you've added.

8. How long will it take to incubate chicken eggs?

The incubation period for chicken eggs is 21 days. You should turn your eggs at least three times a day for the first 18 days, and stop turning after the 18th day (or use a hatcher if you have eggs from different days in the same machine). This allows the chick time to orient itself inside the egg before pipping.

After day 18, KEEP THE INCUBATOR CLOSED except to add water. This will help bring the humidity up to help the chicks hatch. I know it will kill you not to open the incubator 1000 times when it's this close to hatch time, but it's not good for the chicks. If you haven't bought an incubator yet, invest the extra couple bucks in the picture window model. Then you can "see it all" without causing harm to your hatch.

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3. FAQ's on Candling

1. Will all the eggs in my incubator hatch?

It is probable that only 90 percent or less of incubated eggs are fertile. (Not all 90% of eggs will hatch either).
Removal of eggs that can be identified as infertile or dead eliminates possible sources of contamination from the incubator.

Candling can be used to identify some of these eggs.

Shining a light through the egg to observe embryo development is called candling

White or pale eggs are more easily candled than dark or speckled eggs. Many people use small flashlights with lenses that can be focused to candle eggs.

Excellent candlers also can be purchased at a reasonable cost. Simple candling devices can be made by inserting a light into a container and cutting a small hole to emit light, or by taping a cone formed from several thicknesses of paper over the lens of a bright light projector. The hole that allows light to pass from the tip of the cone should be dependant upon the size of the egg.

In a dark room, hold the egg to the light of the candler to observe the contents of the egg. Cooling that occurs for short periods (less than 10 minutes) during careful examination of eggs does not harm the development of the embryo. However, limit the exposure of the egg to the hot light source.

The presence of embryos can be confirmed easily after 8 days to 12 days of incubation.

The embryo is located in the large end of the egg, where blood vessels radiate under the surface of the shell. The embryo appears as a dark spot that becomes larger as incubation progresses. Eventually only a dark mass and the air cell are seen. An infertile or unincubated egg brightly transmits light in comparison. Remove infertile or non-growing eggs from the incubator. If questions arise about candling, contact someone with experience for advice.

Dead embryos will sometimes appear as a ring or smear of blood in the egg or a dark spot dried to the inside of the shell. The living embryo will appear as a dark spot in the large end of the egg surrounded by a faint outline of blood vessels. The blood vessels will appear firm and distinct. After embryo death, the embryo no longer grows and the blood system fades.

Retain records of egg infertility or embryo death. Some mortality can be expected, however, unusual occurrences of mortality or certain characteristics of the mortality can be indicators of practices that can be corrected to improve hatchability.

2. How do I candle eggs?

Shine a bright light through the egg. Candling is not a specific art.

It is more of a comparison, meaning all the eggs of the same age should look the same. It is something best learned by doing it, and really is just as simple as you make it. You cannot hurt eggs by candling them (short of dropping them). They can be out of the incubator for a half-hour without any harm. Candle every day if you like, after day 3 you should see something. At about 8 days, you can see the chick wiggling and kicking in his egg.

3. How do I spot bad eggs?

The egg on the left shows a ring at 6 days. This ring is formed by concentrated bacteria which has invaded the eggs' membrane. It can become present very early, or after the chick has already started to form, as in the picture on the right. In the picture on the right the ring, or portion of it, can be seen at the bottom of the egg with the expired chick in the middle.

For a different reason. The egg on the left shows a blood spot. In my experience an egg with a blood spot will not hatch. They will go bad and blow up, though. The egg on the right at 6 days shows "clear". It is infertile, or too old to germinate.

The egg on the left shows a blood spot incubated to 8 days. You can see the bacterial ring forming at this point. Soon this egg will start to "weep", and if it isn't caught in time, it will explode into a stinky mess. The egg on the right shows highly defined pores. Eggs that look like this under candling have a slim chance of hatching in my experience. I've noticed that it mostly depends on the severity of the porosity.

On the left, you can see the "spider" of veins growing away from the peep. This egg is at 6 days. You can see this spider in a smaller version at 3 days. The egg on the right is at 2 weeks. You can see the clear spot beneath, with the yolk and peep floating at the top.

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