A hen does not need a rooster to lay eggs. However, a hen does need a rooster to fertilize its eggs, otherwise the eggs will not hatch. If the egg is fertilized, the mother hen or a broody hen will care for the egg by keeping it warm until it hatches. While developing, the unhatched chick will eat the yolk in the egg to get the nutrition it needs to grow and develop.
Children will love to help the chick hatch from the egg with this simple chick hatching activity and craft (our inspitation for this craft came from here). Use the craftivity to talk about how the chick grows inside the egg.