How Does a Baby Chick Hatch?

Preparation

Before a baby chick can hatch, the mother hen has to make sure the egg has been properly cared for. The eggs must be kept warm, nearly 100 degrees Fahrenheit, and maintain constant humidity levels of about 55 percent, which is why the mother hen lays on top of the eggs. This is called the incubation period. The mother hen must also turn her eggs to prevent the embryo from sticking to one side of the egg and causing abnormalities. She turns the eggs with her beak several times a day. The entire incubation process takes about 21 days, and the chicks will usually hatch within a day or two of each other. Eggs that have not been fertilized by a rooster will not hatch, and eventually the mother hen will abandon these eggs.

Time to Hatch

The mother hen will hear her chicks chirping from inside the egg. She will then peck a hole in the larger end of the egg. This will help the chicks breathe. She will also cluck, which helps encourage her chicks to break out of their shells. During this long process, the chick will stop to rest, and absorb the yolk from the egg. They will also absorb the portions of the membrane containing a blood supply. Eventually, the chicks will begin to hatch from the egg completely.

Emerging

The chick will soon use its beak to make the hole larger. While inside the egg, the chick will slowly turn its body around, cutting the egg. This will create an opening large enough to allow the chick to emerge from the egg. It will crawl out slowly and usually lie on its side completely wet. It will take a while for the chick to dry out. The chick will actually live off of the yolk of the egg that it absorbed while inside. The mother hen will continue to lay on top of the chicks to keep them warm and protect them.

Hatching Without Mother Hen

Chicks can also hatch without preparation from the mother hen. This happens with artificial incubation. Eggs are kept in incubators that maintain temperatures of nearly 100 degrees Fahrenheit and 55 percent humidity-- just as if they were under the mother hen. Three days before the eggs are supposed to hatch--at the end of the 21-day cycle--the humidity is increased to 70 percent. This helps the egg's shell soften so it's easier for the chicks to hatch. The eggs are also turned either by a human or an automated incubator. The chicks will make the first hole in the egg with their beak and will eventually cut through the shell. Again, they rest for long periods to absorb the nutrients from the yolk. This process takes hours. The chicks eventually break through the egg and emerge wet. They may stay in the incubator a few days after they have hatched.

Resources

• Chicken Breeding
• About Bird Eggs