Embryology & EGG Cam

If you plan to use an incubator to hatch eggs, always carefully read and follow the manufacturer's instructions. Lancaster County schools use GQF manufacturing Company's Genesis Hova-Bator model 1588 (see Hava-Bator instruction manuals). Lancaster County teachers, see Lancaster County 4-H video "Incubator Set Up for 4-H Embryology"

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Guidelines for Successfully Incubating Chickens

Remember to wash your hands before handling the eggs. Proper sanitation is very important to prevent bacteria and other contaminants from entering the pores of the shell.

Chicken eggs take 21 days to hatch. Once a fertilized egg is laid, it will remain viable for 6–7 days when kept at room temperature. The date you set the eggs in the incubator will determine when the chicks will hatch. If you would like them to hatch on a certain date, set the eggs 21 days in advance.

Test your incubator in advance to make sure it is running properly and that the temperature is correct. After testing, unplug your incubator. 24-hours prior to setting your eggs, plug it back in and fill half the troughs with warm water to build up temperature and humidity.

Temperature

Incubator temperature should be 100–102 degrees Fahrenheit. In some incubators, 99 degrees F is acceptable. 103 degrees F and over will kill embryos. When you use a thermometer, place it in the middle of the incubator near the eggs on the screen — not under the screen or at the sides of the incubator. Incubator location is important. Keep it out of drafts and direct sunlight — along an inside wall is best. Ideal room temperature is 70–75 degrees F. If a batch of eggs has trouble hatching, you may need to adjust the temperature the next time you incubate, so keep notes. Often it is the thermometer providing an inaccurate reading. You may want to try a couple of thermometers and take the average. It is very important that incubator temperature remains stable — do not make adjustments during incubation.

IMPORTANT NOTE: In working with local teachers, a temperature of 102 degrees F increased successful hatching rates. This may be because students and teachers open the lids of the incubators to work with the eggs more than in a typical situation. If you are not opening the incubator in a classroom setting, follow the temperature instructions for your incubator model.

Humidity

Humidity should be around 43–44% throughout the 21-day-cycle in the incubator. Keep half the water troughs full at all times. When adding water, warm water is recommended to help keep the temperature steady inside the incubator. Without humidity, the shell and shell membrane will dry out and become tough for the chicks to break through when it is time to hatch. Too much humidity (over 45%) may cause developmental problems. Do not place anything in the incubator such as sponges to absorb humidity. When adding warm water to the incubator, do not to pour any water directly on the eggs. Eggs should not be placed in direct contact with water.

Turning the Eggs

Turning the egg correctly is very important to the development of an embryo. To help you keep track of how to turn the eggs, use a soft lead pencil to mark an X on one side of the egg and leave the other side blank. When the X is up, pick up the egg and place it with the X facing down, and vice versa. Once in the incubator, eggs should be turned three times a day (for example, morning, noon and afternoon/evening). For teachers — on weekends you can turn the eggs once a day. Always turn eggs an odd number of times a day.

Turning provides embryos exercise so they get the proper movement to develop correctly. Some incubators use electronic turners to automatically turn the eggs. In a classroom setting, it is more beneficial for youth to have the hands-on experience of turning the eggs. On the 18th day of incubation, stop turning your eggs. Follow the directions for your incubator — you may need to add warm water. Close the incubator and DO NOT OPEN until after the chicks hatch.

When Chicks Hatch

Chicks will begin pipping (pecking through the shell) around the 21st day of incubation. Pipping will take place for 1–6 hours before the chick emerges from the shell. After emerging from the shell, the chicks begin to dry, move about and become strong. This may take 4–6 hours. It is important to leave the chicks in the incubator until they are completely dry.

Brooder Setup

When you remove the chicks from the incubator, place them in some sort of brooder with supplemental heat. Chicks should be kept at about 95 degrees F for their first week of life. Use a cardboard box, a plastic tote, an aquarium or similar container. Round/oval containers have the benefit of preventing chicks from crowding into corners.

Provide a heat source such as a heat lamp with a heat bulb (recommended) or a desk lamp. You can adjust the temperature by raising and lowering the lamp. Cover the bottom of the container with non-slick bedding such as shredded paper or wood chips to give traction as the chicks walk. Provide chicken feed and water in shallow containers. Lancaster County teachers, see Lancaster County 4-H video "Brooder Setup for 4-H Embryology."

Trouble Shooting and Talking to Youth

Fertile eggs may fail to hatch for a variety of reasons. Incubating eggs isn’t always easy. Sometimes chicks don't survive because of the poor diet of the mother hen or because of the humidity/temperature in an incubator. Eggs held too long (over 6–7 days) before incubation, or held in too warm and/or too dry an atmosphere also decreases chances of fertility. Sometimes chicks which hatch may be born with deformities and do not survive once they break out of the shell. Some embryos/chicks are just too weak and unable to continue development. Teachers and parents should be prepared to discuss these issues with children. Keep in mind, some children may have never experienced death prior to an egg failing to hatch.

Candling is the use of a bright light to shine through an egg to check fertility and embryology development.

See Candling Photos on 4-H Embryology Flickr

Why Candle Eggs?

• If you leave eggs in your incubator that are not fertilized ("yolkers") or have embryos that have quit growing ("quitters"), your incubator (and room) will get very smelly. These eggs rot if left in an incubator!
• You can check to see how the embryos are developing.

How to Candle an Egg

You will need:

• A bright light. When our 4-H staff visit classrooms for candling, we use flashlights with bright LED bulbs.
• A dark room. The room should be near the incubator or in the same room as the incubator so you can put the eggs right back in after you are done.

If you are nervous about handling one of your eggs, practice first with an egg you bought from a grocery store. These eggs are not fertile.

When you are ready, turn on your bright light and shut off the lights in the room so it is dark. Without looking directly at the bright light, hold the larger end of the egg (which has the air sac) up to the light and slowly rotate the egg to see various structures within. The light won't hurt the embryo, but it isn't a good idea to hold the light up to the egg a long time, especially if the light gets hot.

Be very careful when you are holding the egg so you don't accidentally crack it.

When you are finished, carefully place the egg back in the incubator. After handling eggs, the incubator or chicks, wash your hands carefully.

What You May See

Do you see the air sac? Can you see the pores in the egg shell? Can you see the yolk? Do you see blood vessels or a thin red ring around the yolk? If the egg has been in the incubator for a week, you may see the embryo move! If your egg is colored or a brown egg, it is harder to see through the shell, you may want to wait a few days and try again.

Winners — When embryos have developed, we call them "winners." In the first few days, you may see a network of blood vessels. About day 7, you should be able to see the shadow of the embryo's body, its eye (which looks like a small black circle) and perhaps movement! The closer the embryo gets to day 21, the more blood vessels and structures you may recognize (such as the beak and feet).

Quitters — When embryos stop growing, we call them "quitters." You will see a thin, blood ring around the yolk. Quitters are removed from the incubator and thrown away. If you want to view the embryo, have your parent or teacher help you open the egg. Be sure to wash your hands afterwards.

Yolkers — Some eggs in the incubator may not be fertile. We call those "yolkers." When you look at a yolker, you won't see a spot in the yolk, blood vessels or a blood ring around the yolk. When we candle eggs in the classrooms and find a "yolker," students usually ask "Can you eat a yolker?" The answer is no — don't eat any eggs that have been in an incubator! Throw yolkers away.