We bought 2 rabbits earlier in the Summer. They have a chicken coup for a hutch. We have gradually enclosed it with perspex as it was open to the elements. I have heard people put tarpaulins over hutches in winter to keep the elements out. Our hutch is water and wind tight (except for an air vent). It is an awkward shape to be able to buy a proper cover for it. Do you think is needs covering for added warmth?