Hello, here's my setup.
Our first kits were born in burrows underground, but as winter came, we decided to give them some nest boxes for the purpose, to make it easier to monitor how the kits were doing in our cold temps. Here's what I came up with:
So far, the coldest we've had has been about -25C (-15F), with 2 week old kits surviving through that no problem. We just had one litter last week, and they've been through -18C (0F) at one day old. As for the grownups, they've had no problems.
These next parts require you to have taken a look at that link I posted. The only thing I've done as winter proofing is covering two sides of the open bottom part of the pen with clear plastic to keep snow out. The bunnies also have heated waterers to keep them hydrated at all times. I was a bit worried about our bunnies going into the winter months at first, but they really don't seem to mind the cold. Even the three week olds hang out in sub zero (F) temps and don't seem to mind it. Oh, and that nest box showed in the pics earlier, I've got one in the downstairs department, and two upstairs. Due to a new addition to our bunnies we had to separate the top from the bottom, so the ones living there don't have a chance to burrow underground like their downstairs neighbors, so they've got one box to sleep in, and the other to keep kits in, while the downstairs guys seemed to only use the plastic box until the kits were old enough to move out, after that all of them have been sleeping underground.
The pic of the nest box in use is from this fall, now in wintertime I've made sure that it's stuffed full of straw, so that it provides some insulation also on the sides and top.
Edited by vehve - 1/20/16 at 1:45am