I read and read and read all about chickens and winters on BYC before getting chicks this fall. Last night 2 of my Black Australorp roosters spend the night out of the coop (oops- although our run is very predator proof) and it was -15F last night. In the coop were the other 16 RIR, RIW and B.As...and the thermometer read -8F as the low. I do have a 100watt heat lamp in the coop on cold nights and a heated waterer. Now, I know that chickens are hearty. Everyone was alright this morning! Although, I will make sure to get all in the coop on cold nights. Its just good to know they can fare just fine in cold weather.