When my daughter had pet rabbits, the hutch was against a wall but still exposed to cold winds and winter weather. I used a sheet of clear acrylic to just insert in the door frame and held against the frame by friction. Hole cut for water bottle. The top of the hutch covered by old carpet to protect from frost. The other thing I learnt from my Dad was to make a loo in one corner. A piece of alloy sheet with edges turned up and a tube secured with plastic filler. A jar underneath collected the urine. This kept the hutch clean.