Here in the Twin Cities, it is expected to be -20 tonight. That's not wind chill (which is going to be around -40) - those are real temps. Last night, because of ice and blowing snow, they actually closed down the Interstate. Today, at the warmest part of the day, it was -1. My girls (I only have 4) have been locked up for 2 days now. Still getting along fine and no fighting that I can hear (over the monitor). I am really glad that I built my coop with about 12 sq. ft. per bird - that's WAY over the recommended amount, but now with the weather on a bad streak that is expected to last several more days, they will have to stay inside. They have a large southern window and plenty of room to party (and get away from each other). I'm not feeling guilty about leaving them inside. In another 2 days I may have a different opinion, but for now it is working out. The down side to too much square footage is that it is VERY hard to keep warm. With such a small flock, body heat doesn't add up to diddly. Being draft free is a huge help, but -0- is still -0-. I'm not writing this post to whine about the cold. I just know that when I was researching coop designs, I could spend HOURS going over posts and trying to learn from other's mistakes/advice. When folks say "Build Bigger" they really do mean it. It's the best piece of advice that I took to heart. And I can only speak for myself, but I am also very glad now that I spent the extra time and money to fully insulate both the walls and the roof. With tonight's temps, I don't think I would be able to sleep knowing that the girls were outside.