I'm putting together a rabbit hutch/tractor (I found the most awesome wheels, I'm so excited!) anyway, we lost a rabbit to the heat this summer, so I wanted to put some kind of insulation at least in the roof, but I don't have room for traditional insulation (plus I'm trying to do this from items on hand as much as possible.) someone mentioned they used carboard as insulation. If I used a few sheets between the 2x4 rafters, would that create enough pockets of air to keep the heat down in the summer/ heat in during the winter? Even a few degrees would help. If this goes well, I might try to make a chicken tractor off of a similar plan next spring for mating trios or juveniles.