What I was observing was probably best described as extreme lethargy, even my most skittish hens didn't react much at all when I came in to the coop and began to handle them. They were very tightly huddled together most with only one foot on the roost the other tucked into their feathers. The ones that I nearly lost and the one that I did didnt respond at all when I was handling them, I could feel and see respirations but they didn't even try to move when I picked them up. The coop is draft free but not insulated, with high vent holes, no one has any frostbite.So sorry you lost a hen to bitter cold! I wonder if you would post the signs of moderate to extreme stress that you observed? And -20F is ultra cold for chickens for sure. I am glad you were able to save them!
I did take one lamp out last night and the other one this morning as our temps remained above 0 last night and seem to be creeping into the single digits today and warming over the next few days.