Ridgetop
Herd Master
If you need to insulate the hutches, a double wall stuffed with insulation would work as long as the rabbits can't get to it. I would not use fiberglass insulation but there is new insulation made of recycled fabric. If you know someone with sheep that doesn't use the wool, you can use that to stuff the walls. You couldn't keep the insulated walls on the hutches in summer though since the rabbits would get too hot. The insulated double wall panels would have to be able to be attached to the sides and then removed. You would still need the drywall pieces for the rabbits to sit on in the cold weather.