Hatching Fertile Eggs

Hatching eggs is an art to hatching your own eggs or raising day old chicks that you have bought. Below you will find tips and tricks to help you decide which direction you might like to go in.

Starting your own flock from scratch. Will you hatch under a broody hen or artificial incubation? With incubators there are many important factors to consider. Generally these factors can be divided into three categories: choosing the right eggs, selecting an incubator and maintaining proper incubator conditions.

If you decide to go natural with a broody hen things are a little less complicated. The other alternatives are buying in already laying hens or point of lay pullets.

Hatching with Broody hen

If you've opted for the natural choice of buying a broody hen, or you already have one, that is a great place to start. You can buy fertilised eggs, let her incubate her own or set a mixture of your backyard flocks eggs for her to sit on, hatch out and raise herself. As a general rule a good sized hen will be comfortable on 15 eggs.

You can also incubate Cortunix Quail eggs under a bantam, and a larger hen will happily sit on and hatch out duck eggs, though she might get a little upset when her precious babies take to the water. Chickens will also sit on Pheasant, Guinea Fowl, Pea Fowl, Turkey and some larger hens may sit on Goose eggs.

There is no beating a mother hen when it comes to hatching and raising chicks. To tell if your mother hen is is clucky/broody is easy, she will stay on the nest almost 24 hours a day, depending on the hen, she may get off for 30mins to 1 hour, this is natural. For the first few days she may get on and off the nest irregularly, if this happens she is not 100% brooding.

It's important to set eggs all at the same time so the chicks inside all develop at the same rate. If you've ordered eggs or are collecting eggs to set at the same time a good way to keep a hen clucky is by placing golf balls or egg sized stones under her. You can also purchase fake eggs for this purpose from some pet shops, farm and rural supply stores. If you've ordered some eggs and they're coming through the post it is a good idea to rest the eggs for about a day so the egg sack inside the egg can return to it's normal size and the embryo can settle.

To set eggs under a clucky hen is fairly easy. This must be done at night. Pick her up, move her to one side, remove Golf balls or fake eggs and set the desired eggs! Try not to disturb her too much during incubation which could cause her to abondon the clutch.

After incubation usually 20-21 days the chicks can be fed starter crumble. Make sure the mother and chicks have access to water that isn't too deep for the chicks to fall in and drown

Hatching With Incubator

Care of Hatching Eggs

Before setting eggs in an incubator, you must obtain or produce quality fertile eggs from a wellmanaged, healthy flock which are fed properly balanced diets.

1. Keep the nest full of clean, dry litter. Collect the eggs early in the morning and frequently during the day to prevent excessive chilling or heating of the eggs.

2. DO NOT wash eggs unless necessary. If it is necessary to wash eggs always use a damp cloth with water warmer than the egg. This causes the egg to sweat the dirt out of the pores. Never use water cooler than the egg. Also, do not soak the eggs in water. If the egg is allowed to soak in water for a period of time, the temperature difference can equalize and bacteria has a greater chance of entering through the pores. Be sure eggs are dry before storing. Never place damp or wet eggs in a styrofoam carton for storage.

3. Store the clean fertile eggs in an area which is kept at 55°- 60°F and 70-75% humidity. Never store eggs at temperatures about 75°F and at humidities lower than 40%. These conditions can decrease hatchability dramatically in a very short period of time.

Slant or turn the fertile eggs daily while they are being stored. Store the eggs small end down and slanted at 30-45 degrees. Putting a piece of 2" x 4" under one end of the carton or storage container and changing it to the other end daily works well.

Do not store eggs for more than 10-14 days. After 14 days of storage, hatchability begins to decline significantly.

4. Just before setting the eggs, allow them to warm to room temperature (70-80°F) and remove any cracked eggs.


Four factors are of major importance in incubating eggs artificially: temperature, humidity, ventilation and turning. Of these factors, temperature is the most critical. However, humidity tends to be overlooked and causes many hatching problems. Extensive research has shown that the optimum incubator temperature is 100°F when relative humidity is 60 percent.

Concentrations of oxygen should be above 20 percent, carbon dioxide should be below 0.5 percent, and air movement past the egg should be 12 cubic feet per minute.

There are two types of incubators commonly used:

1. Forced-air incubators which have a built in fan to circulate the air.
2. Still-air incubators which have no fans, so the air is allowed to stratify.

The forced-air incubator should be set at 99-99.5°F and 60-65% relative humidity (83-88°F wet bulb). The advantage of the forced-air incubator is that it is easier to maintain humidity at a constant level because of air circulation.

Still air incubators are smaller and air flow is harder to manage. Set still-air incubators at 100 to 101°F at egg height. This is important since the air stratifies in these incubators. There can be as much as a 5° difference in temperature from the top to the bottom of some of the still-air incubators. Humidity should be 60-65% (80-90° wet bulb) during incubation and 70-75% (92-97° wet bulb) at hatching time. It is very easy to overheat the eggs in still-air incubators and difficult to maintain proper humidity.


During the warm-up period, the temperature should be adjusted to hold a constant 101°F for still air, 99°- 100°F for forced air. To obtain reliable readings, the bulb of the thermometer should be at the same height as the tops of the eggs and away from the source of heat. Using two thermometers is a good idea to ensure you are getting an accurate reading.

Incubator temperature should be maintained between 99° and 100°F. The acceptable range is 97° to 102°F. Mortality is seen if the temperature drops below 96°F or rises above 103°F for a number of hours. If the temperature stays at either extreme for several days, the eggs may not hatch. Overheating is more critical than underheating. Running the incubator at 105°F for 15 minutes will seriously affect the embryos, while running it at 95° for 3 or 4 hours will only slow the chick's metabolic rate.

An incubator should be operated in a location free from drafts and direct sunlight. An incubator should also be operated for several hours with water placed in a pan to stabilize its internal atmosphere before fertile eggs are set. Do not adjust the heat upward during the first 48 hours after eggs are set. This practice cooks many eggs. The eggs will take time to warm to incubator temperature and many times in small incubators the incubator temperature will drop below 98°F for the first 6-8 hours or until the egg
warms to 99°-100°F.

In Case of Power Outage

If you experience a power failure, do not scrap the hatch. Most of the time the hatch can be saved. The key is to keep the eggs as warm as possible until the power returns.

This can be done by placing a large cardboard box or blankets over the top of small incubators for additional insulation. To warm the eggs, place candles in jars, light them and place the jars under the box that covers the incubator. Be careful not to put any flammable material closer than a foot from the top of the candles. The heat from the candles can easily keep the eggs above 90°F until the power returns.

Embryos have survived at temperatures below 90°F for up to 18 hours. You should continue to incubate the eggs after the outage; then candle them 4 to 6 days later to check for further development or signs of life. If, after 6 days, you do not see life or development in any of the eggs, then terminate incubation. Most of the time, a power outage will delay hatching by a few days and decrease the hatchability to 40- 50 percent.


The relative humidity of the air within an incubator should be about 60 percent. During the last 3 days (the hatching period) the relative humidity should be nearer 65-70 percent. (Too much moisture in the incubator prevents normal evaporation and results in a decreased hatch, but excessive moisture is seldom a problem in small incubators.) Too little moisture results in excessive evaporation, causing chicks to stick to the shell, remain in the pipped shells, and sometimes hatch crippled.

The relative humidity in the incubator can also be varied by changing the size of the water pan or by putting a sponge in the pan to increase the evaporative surface. The pan should be checked regularly while the incubator is in use to be sure that there is always an adequate amount of water. Adding
additional water pans to small still-air incubators is also helpful to increase humidity.

During the hatching period, the humidity in the incubator may be increased by using an atomizer to spray a small amount of water into the ventilating holes. (This is especially helpful when duck or goose eggs are hatching.)

Whenever you add water to an incubator, it should be about the same temperature as the incubator so you do not stress the eggs or the incubator. A good test is to add water just warm to the touch.

Using a wet-bulb thermometer is also a good way for determining relative humidity. The wet-bulb thermometer measures the evaporative cooling effect. If the wet and dry bulb read the same temperature, you would have 100 percent humidity. The greater the evaporation taking place, the lower the temperature reading on the wet-bulb thermometer and the larger the spread will be between the wet- and dry-bulb readings.

To make a wet-bulb thermometer, just add a cotton wick to the end of a thermometer. Then place the tail of the wick in water. The cotton then absorbs the water. As the water evaporates from the cotton it causes a cooling effect on the thermometer.


The best hatching results are obtained with normal atmospheric air, which usually contains 20-21 percent oxygen. It is difficult to provide too much oxygen, but a deficiency is possible. Make sure that the ventilation holes are adjusted to allow a normal exchange of air.

This is critical on home-made incubators. It is possible to suffocate the eggs and chicks in an air-tight container. However, excessive ventilation removes humidity and makes it difficult to heat incubators properly.


Eggs set on their sides must be rotated 1/2 turn at least 3 times daily. Eggs set with the air cell end up should be tilted in the opposite direction 3 times daily. This keeps the embryo centered in the egg and prevents it from sticking to the shell membrane. If hand turning, to insure proper turning, mark each side of the egg with a pencil. Put an "x" on one side and an "o" on the opposite side.

Stop turning the eggs for the last three (3) days of the incubation cycle (at 18 days for chickens, 25 days for waterfowl, etc.) and do not open the incubator until the hatch is completed to insure that a desirable hatching humidity is maintained.

Hatch Time

Do not help the chicks from the shell at hatching time. If it doesn't hatch, there is usually a good reason. Also, prematurely helping the chick hatch could cripple or infect the chick. Humidity is critical at hatching time. Don't allow your curiosity to damage your hatch.

As soon as the chicks are dry and fluffy or 6 to 12 hours after hatching, remove the chicks from the incubator. It is good practice to remove all the chicks at once and destroy any late hatching eggs.

Hatching time can be hereditary and you can control the uniformity of hatching by culling late hatchers. If you keep every chick which hatches late, in a few years each hatch could last 4 days or longer.

Sanitation of Incubator and Equipment

No matter what type of incubation you use, it is important that you thoroughly clean and disinfect the
incubator before and after you use it. It is just as important that the incubation room and egg storage area are kept equally clean. The lack of sanitation will decrease hatchability.

Immediately after each hatch, thoroughly clean and disinfect all hatching trays, water pans and the floor of the hatcher. Scrape off all egg shells and adhering dirt. Wipe clean surfaces thoroughly with a cloth dampened in quaternary ammonium, chlorox or other disinfectant solution.
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Accurate Temperature For Hatching Eggs

The incubation temperature requirements for most hatching eggs is surprisingly uniform. The eggs of almost all domestic bird species (and many wild species) can be incubated at the same incubation temperature. Therefore, eggs of several different bird species can be incubated at the same time within the same incubator.

The incubation temperature of naturally (nest) incubated eggs is controlled by the hen. The recommended temperature within an artificial incubator depends upon the type of incubator being used. If the incubator used has a fan for air circulation, the temperature must be adjusted to 99-100o F.

An incubator without an air circulation system requires a higher temperature. The temperature in this "still-air" incubator is measured using a thermometer with the bulb positioned at the same level as the top of the incubating eggs. The recommended temperature in this type incubator is 102o F.

The reason for different temperatures is that circulating air warms all points around the egg shell while still air temperatures are warmer at the top of the egg than at the bottom. Therefore, increasing the temperature at the top of the egg will compensate for the egg's cooler parts. The same average egg temperature of 100o F can be maintained (for the entire egg) if the higher temperature of 102o F exists at the egg's uppermost point.

Do not allow temperatures to exceed these recommendations, even for only a short period of time. Although it is not recommended, slightly lower temperatures will not kill the chick embryos, but can increase incubation times and produce weakened chicks. Temperatures only a degree or two above the recommended temperatures can kill chicks within 15-30 minutes, depending on how high the temperature is and the stage of development of the chick embryo.
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Candling Eggs

Fertile eggs
Eggs are candled to determine the condition of the air cell, yolk, and white. Candling detects bloody whites, blood spots, or meat spots, and enables observation of germ development. Candling is done in a darkened room with the egg held before a light. The light penetrates the egg and makes it possible to observe the inside of the egg.

The candler should be set on a box or table at a convenient height (about 38 to 44 inches from the floor), so the light will not shine directly into the eyes of the operator. In candling, the egg is held in a slanting position with the large end against the hole in the candler. The egg is grasped by the small end and, while held between the thumb and tips of the first two fingers, is turned quickly to the right or left. This moves the contents of the egg and throws the yolk nearer the shell. Because of the color of their shells, brown eggs are more difficult to candle than white eggs.

To do a reasonable job, an extensive knowledge of candling is not necessary, particularly if the eggs are all relatively fresh. One should be able to distinguish a fresh egg from a stale egg and detect such abnormalities as bloody whites, blood spots, meat spots, and cracked shells. In a fresh egg, the air space is plainly visible and moves freely. The white is thin and clear. In a stale egg, the air space is plainly visible and moves freely. The white is thin.

Most newly laid eggs are good quality. Eggs not over two or three days old, if held under good conditions, will meet the specifications for Grade A. The only eggs to be removed by candling are those with bloody whites, blood or meat spots, and cracked shells.

Candling Eggs
Candling is a way of checking the fertility of an egg and the development of the embryo, with the use of a light source in a darkened room. In a darkened room, carefully hold the egg up to the light to observe the contents of the egg.

Candling Results
The embryo is located at the large end of the egg, where blood vessels will be present under the surface if the egg is fertile. The embryo appears as a dark spot which becomes larger as the incubation period continues.

Fertile egg
The egg will appear to have a black spot which as the embryo grows and incubation continues will grow larger until light will only pass through the air cell end of the egg.

Infertile egg
Eggs appear clear.

Dead embryo
If the egg was fertile but the embryo has died then you will see a blood ring around the yolk or possibly a dark spot dried to the inside of the shell depending on when the embryo stopped growing.
Note that dark or brown shelled eggs are more difficult to candle than white or pale shelled eggs.

When To Candle
Candling can be done at any time, although day 8 onwards is usually when the embryo is more easily identified.
Day 3 of incubation (usually pale shelled eggs).
Day 5/6 of incubation (usually dark shelled eggs).
Between day 8 - 12 of incubation (embryo more easily identified).
3 days prior to hatching.

How To Candle
To candle, darken the room. Eggs can be out of the incubator (or away from a broody hen) for up to 20-30 minutes before starting to cool down inside, so don't rush. You can GENTLY roll the egg on the candler to get the best view.
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Poor results in hatching

Hatching Eggs
Poor results in hatching are commonly caused by the improper control of temperature or humidity. When the temperature or humidity is too high or too low for a long period of time, the normal growth and development of the embryo is affected.

To obtain the best possible hatch, keep the temperature as near 100.5 degrees F. as possible for the entire incubation period in a still air incubator. There will be a fluctuation of two or three degrees above or below 100.5 degrees F., but there should not be prolonged periods of high or low temperatures. High temperature is especially serious.

An incubator that is run warm, constantly averaging a bit above 100.5 degrees F will tend to produce an early hatch. One that is run cold, a bit below 100.5 degrees F will tend to produce a late hatch.

To obtain the proper temperature reading, place the bulb of the thermometer so that it is on a level with the place where the embryos will begin to develop in the eggs. This is approximately 1/4 inch below the top surface of the shell when the egg is on its side. This applies to chicken, duck, pheasant, quail, and other species' eggs. The bulb of the thermometer should not be in contact with an egg.

Check the thermometer. Is it accurate? An error of one degree for 21 days can seriously interfere with embryonic growth.

To check the incubator thermometer, place the bulb next to the bulb of a clinical (the oral kind used to check body temperature) or a laboratory thermometer. Hold under lukewarm tap water and compare the readings. Make an adjustment for any error in the incubator thermometer.

A thermometer in which the mercury column is split will not give an accurate reading.

Rarely is the humidity too high in a still-air incubator. Normally, it tends to be low. Thus, the water pan should cover at least one-half of the surface area of the incubator.

The humidity should be raised during the last three days of incubation. Adding another water pan or a wet sponge helps to do this. Embryos need considerable moisture to hatch properly and easily. High humidity tends to produce a late hatch; low humidity an early hatch.

Do not turn the eggs the last three days of incubation. The embryos are moving into hatching position and do not need to be turned. Keep the incubator closed to maintain proper temperature and humidity, but Do not seal it tight for the embryo needs oxygen.

Don't forget to place a cloth, crinoline is best, on the screen floor of the incubator. This protects the navel, the place where the abdomen closes after surrounding the remains of the yolk, from injury. It also makes cleaning the incubator easier. The longer eggs are held before setting, the lower the fertility will be. Try to set eggs before they are ten days old. At three weeks, the fertility will drop to zero.

Allow the newly hatched chicks to dry out in the incubator until they fluff up. Then place them in a brooding unit.
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