I have 2 that refuse to be caged and refuse to go in the barn.. they are in a spacious hutch.
Tonight it is 31 degree's outside. They have a seperating wall between them, and they also have the drop through mesh floor.
Here is what we have done for them, and they have survived 4 winters of temps in the teens.
We give them a meal of rolled oats, crimped barley and black oil sunflower seeds with some cheerios rolled in wheat germ oil. The ONLY thing that is majorly important in that is the black oil sunflower seeds.. it increases their core temp. The other stuff just basically insures they gobble everything down including the sunflower seeds.
We gave them each a nice heaping of hay early in the day for them to *nest* the way they like.
Keeping the North wind off is critical. My husband cuts 2 pieces of plywood the same side as the end of the hutch and screws that end. The opposite side doesn't really need it, as it is not facing the North side, but I like to add to the cozy feel. We then take a flannel blanket and wrap the front, using clothes pins to secure it to the wire. top sides and bottom, THEN we get a Wal-Mart $4 blue tarp and some bungee cords. We usually already have some screws in for the cords to hook on.. REALLY keeps the wind off.... bungee em on each corner.. tight.
If it gets REALLY cold.. like tonight.. we have a clamp light with a heat lamp on the top of the hutch. Aimed between the two, and the usually nest down underneath the lamp. There is a space of about 4 feet between the heat lamp and the hay and the buns..
Zin