A hen can lay an egg whether or not a chick will grow inside it. To begin growing into a chick, an egg must first be fertilized.
Fun fact: A hen is a female chicken; a rooster is a male chicken.
Discover what a chicken egg needs to develop, how a chick grows, and how it hatches.
Why Some Eggs Have Baby Chicks
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If a fertilized egg is kept warm in the right conditions, an embryo can develop inside. The yolk supplies much of its food.
Fun fact: An incubator can provide warmth when a hen is not sitting on the eggs.
Over about three weeks, the chick grows and changes inside the shell. The shell has tiny pores that let gases move in and out.
Fun fact: The shell's tiny pores let oxygen reach the growing chick.
When it is ready, the chick breaks through the shell using a small bump on its beak called an egg tooth. Eggs sold for food are usually not incubated for chicks.
Fun fact: The egg tooth is temporary and falls off after hatching.