Use the adjective oviparous to describe an animal that lays eggs. Birds and lizards are oviparous.
A chicken is a good example of an oviparous animal, since females lay eggs and then keep them warm and safe until they hatch. In fact, all birds are oviparous, as are most fish, reptiles, and insects. The word oviparous is most often used in biology classes to distinguish egg-laying animals from those that give birth to live babies, like humans. It's a Latin word that combines ovum, or "egg" with parere, "to bring forth."