Life cycle of a chicken biology lesson for kids: 1st, 2nd, 3rd, 4th, 5th, 6th and 7th grades biology lesson.
People have been rearing chickens for thousands of years for food, since we eat their meat and their eggs. There are so many chickens on Earth that they outnumber humans seven to one! They have a very simple life cycle, as you will see.
Every chicken starts as an egg. The female chicken, called a hen, lays the eggs and sits on them, keeping them warm with her soft body. An egg contains yolk in the center, which contains all the nutrients the growing baby chicken, called an embryo, needs to grow. The yolk is surrounded by a clear liquid called albumin. You might know the albumin as the “egg white”, but it only turns white when the egg is cooked. The albumin’s main purpose is to protect the yolk and the embryo inside.
The embryo grows inside the egg for about twenty-one days, sucking up all it needs from the yolk, until it is ready to hatch. When it is big enough, it starts pecking through the egg shell, breaking itself out. Because the egg shell is so strong, and the baby is so weak, this can take hours. When the baby hatches, it is called a chick, and it is wet and because of the albumin inside the egg.
Over time, though, the chick will dry and it will be fluffy because of its feathers. Amazingly, chicks don’t need to eat for two whole days after hatching, because they absorb the yolk into their bodies while still in the egg, and get sustenance from it after they hatch. After that, chicks eat a whole lot and grow very fast. They eat things like corn and grain.
As they get bigger, they become pullets, which are kind of like the chicken version of teenagers. Pullets spend a lot of their lives learning how to be adult chickens from grown up ones around them.
At around eighteen weeks old, the female pullets start laying eggs of their own. When they do, they’re adults now, and are called hens. Not all eggs will hatch, though, only fertilized eggs will. An egg can only be fertilized if the hen mates with an adult male chicken, a rooster. Roosters are bigger than hens and have bigger red growths on the top of their heads called combs, and that hang from the bottom of their heads called wattles. When a hen mates with a rooster, she can decide if she wants to keep his genes for her babies, or if she wants to get rid of them. The ones that she chooses to keep fertilize her eggs, and when she lays then, she takes care of them until they’re ready to hatch, and the cycle continues!
And that is the life cycle of a chicken.