Great information. Last winter when it got down to 18 below 2 nights in a row, my flock was in an unheated (insulated, ventilate through the eaves and roof peak) coop. We did put heavy clear plastic over the windows because they were leaking air. I didn't lose a bird. I did take them pellet mash (warm) first thing in the morning and put it on their roosts to keep them eating.
