Who laid the eggs?

Eggs, like rabbits and hares, are fertility symbols of extreme antiquity; since birds lay eggs and rabbits and hares give birth (to large litters) in the early spring, these became symbols of the rising fertility of the earth at the Vernal Equinox.

The saying "mad as a March Hare" refers to the wild caperings of hares as the males fight over the females in the early spring, then attempt to mate with them. It is therefore not surprising that rabbits and hares should become fertility symbols, or that their springtime mating antics should enter into Easter folklore; however, the notion of a rabbit that lays eggs has an uncertain past. It may have simply arisen from a confusion of symbolism but, like much of the holiday of Easter itself, it could be a direct heritage from older traditions.

In Germanic and Slavic languages, the word "Easter" comes from an ancient pagan goddess of the spring named Eostre. According to legend, Eostre once saved a bird whose wings had frozen during the winter by turning it into a rabbit. Because the rabbit had once been a bird, it could still lay eggs, and that rabbit became the modern Easter Bunny.

Source: Wikipedia