On average, it takes 21 days for a fertilized chicken egg to hatch into a healthy chick. It takes about 21 days for a chick to hatch, give or take a few. If you are trying to hatch your own chicks, you will need to familiarize yourself with the basics of egg care or you could put the health of your chicks at risk.
Chickens lay an average of one egg every 25 to 26 hours. Eggs are formed when the ovum, otherwise known as the yolk, develops within the ovary and is released during ovulation. The yolk passes down from the ovary and into the oviduct, where it develops the egg white and the shell. Fertilization takes place while the egg is inside the oviduct. The egg passes out of the oviduct through the vagina. Any physical abnormalities with the egg are likely to occur during the formation process. The average hen will lay 250 to 270 eggs each year.
The Natural Process
When a hen decides she wants to sit on her eggs and hatch them, she is referred to as being broody . Broody hens will lay a clutch of eggs and sit on them and care for them until they hatch. The average clutch of eggs contains between three and eight eggs. Your hen will need to be provided with food, water and a living space free of predators. She will keep the eggs warm and periodically turn them so the developing chicks stay viable and healthy.
You can hatch fertilized chicken eggs without the help of a hen. Incubators are designed to keep chicken eggs warm and moist, providing them with the necessary environment for healthy development until they hatch. Eggs should be placed into the incubator within seven days of being laid. The temperature inside the incubator should be between 99 and 102 degrees, depending on the style of incubator. Turn the eggs regularly to minimize the likelihood that the chick will become stuck to the inside of the shell and grow abnormally.
During incubation, you can use a process called candling to check on your chicks to see if they are developing inside the egg. Candling involves putting the egg up to a shielded light so the contents of the egg can be seen partially through the shell. If the egg looks clear, you do not have an embryo developing. As time passes, more and more of the inside of the egg should appear dark in color. This is the embryo developing and growing. If the embryo stops developing, it most likely died.
Not all eggs will be fertile and you cannot expect 100 percent of your fertilized eggs to hatch. The length of time it takes your chicks to hatch can be affected by environmental temperatures. Chicks who are kept in too cool temperatures may hatch late, while those who are kept in too warm temperatures may hatch early. Some chicks may die prior to hatching due to being exposed to conditions that are too hot or too cold. You can leave unhatched eggs in the incubator for a day or two after the 21-day incubation period just in case any of your chicks are late hatchers. If chicks have not hatched after day 23, they are probably not going to.