They are inside an insulated barn. I haven’t been using artificial heating after much consideration and discussion with others in my area. They have very deep bedding that I keep very clean and dry and they are safe from drafts but still have good ventilation. Inside the barn, they are in a stall at night. Inside the stall, they have lots of cozy nesting options. I did cave and buy a chicken warming pad, but haven’t used it yet. Most days have not been quite as cold as last night. Mostly, it is in the 20s during the day and teens to low 20s at night, which they are fine with. So far, so good!