When they stop growing? We had someone give us a gray/brown bunny in early July, the idea being that he would make a nice companion for our female black rabbit, but it got super hot, and when i went out to bring them inside, she had died. It was so horrible that our male is now inside full time. Anyway, he was two months old when he came to live with us and has nearly doubled in size since the Fourth. I was told he was a small breed and am starting to wonder if we're going to have to do something about a much bigger cage. At what age do they stop growing?