How many days do you think it takes for a chick to hatch after the egg has been fertilised? If you think of a human the gestation period is nine months. For a chick it is 21 days so the chick does a lot of growing very quickly. 

The mother hen lays her eggs in a nest and then sits on the eggs to keep them warm. The chick is protected by the hard shell of the egg. If you look carefully you will see that by the fourth specimen the chick has the beginning of a dark feathery covering and well defined beak and claws.

The fully grown chick hatches out of the egg by pecking its way with a special egg tooth on its beak. This can take up to a day. When the chick hatches it is wet and sticky. Its feathers are called down. The chick can walk immediately and likes to eat seeds and bugs.  Chicks grow more feathers after about four weeks together with a comb on their head and a wattle on their beak. They look like their parents from the time they hatch and it takes about six months for them to become fully grown.

This specimen shows six stages in a chick’s development inside the egg.