It regularly gets to -20°F and usually a short spell of -30°F here every winter. The coop door is closed at night but the bird door is open every day. If the poultry wants to be out in the weather, it is their choice but they do get the choice.In the area I live, it's not uncommon to get to -20. Though rare, I've seen -80 with a wind chill (hell on earth). I should have been more clear, but I'm particularly wondering about the days when it hurts to be outside...id say that's somewhere around -20 to -40. In cases where it is severe cold, do you keep them in?