We (BB aka baby brother who lives with me) have new batches of wild rabbits often, especially in the Spring, born under our front and back porch.  When we first notice them, they are probably only about the size of my hand.  I don't have a small hand, that would be odd on a person as tall as I am.  I have often wondered when they are first allowed out of the nest on their own.  I still wonder that.