I live in canada and i use barrels. They work fine up to-20°. Just have canopys an small doors.
Lots of fresh straw n' shavings mix. And your set. I got tired of building 10 houses a year cause of chewing, and urin soaked wood. I dont use flaps on the doors, cause it take you 40mins. To put on/make. And they take 30sec. To rip it off.