My poor chickens got frozen combs. I rushed in and insulated the coop quickly and put a heater in there to warm it up. one hen i had to bring her in the house and give her a warm bath and hot blowdry cause she had a big ball of ice poo stuck to her rear. Poor thing was so uncomfortable. She sure loved that warm bath though and blowdry. I think they'll all be fine now. My one rooster got the worst as far as a frostbit comb. Record cold tempertures up here in the Yukon this year.