Great coop JackE. As I said, I'm in Minnesota, this is my first winter with chickens. this whole week it has been in the single digits at night (2 degrees F this morning). They seem fine in the coop where there is no wind, I put my hand under them and they feel warm on the roost still. I've put up greenhouse panels around 3 sides of their run, west, north and east. I left the south side open to the sun with just hardware cloth, all this week when i've come home from work they have been outside the run and it was only in the teens sometimes. They don't seem to care. We'll see what happens as it gets colder...