Well, so far I haven't lost any. I just moved the 7 week olds out there in a brooder with an extra light. There's still several feet of snow on the ground and it's 8 degrees this morning. My front wall is still a blue tarp. It's inside the barn, but the barn is always open. Some of them got a touch of frostbite on their combs during the -20 week, but other than that all is good!