there are indoor rabbit cages that some people use for hatchlings outside, these come in different sizes upto about 4 or 5ft long, one type have a deep plastic bottom, plastic sides and a cage meshtop, the plastic sides will help prevent draughts and keep the warmth in, the other type are a deep plastic bottom, and a cage top. I have one of these for my little star when the weather is nice enough for her to go out.