I've been fretting over my hens - They have a nice, big coop, and a run, and they free range during the day. But it is in the low to mid-20's here at night, and I worry about them. They seem to be completely fine. I thought maybe they would want to stay inside today (the temp never got over 30), but they were out like a flash when I opened the door, and came back at dusk, as usual.
I must say, when they are all inside for a while, it is much cozier! I do have a heated water base for their metal waterer, since it is freezing solid without the heater. Even so, it had come unplugged one night, and the girls were fine until they got out to scavenge for water the next morning.
I had the same worries about my horses our first year here, until I realized that given the choice, they would shun their cozy run-ins to stay outside in the sleet. They looked like Yeti's most of the time, and were snug and warm in their winter coats. I am assuming the hens have a similar heat system (god knows that if I was freezing I would want to cuddle up under a mess of chickens - they really put out some heat!!)
Kate