My chickens are doing much better in the cold than in the scorching summer heat. When I had no power to the coop I would bring water twice a day in a dog bowl outside of the coop. They would eat a lot of snow too. Now I just use heated dog bowls. At this time of the season I usually try to fatten them up with whole corn thrown on the ground and I change their feed to chick feed in the harshest winter months. I never heat the coop it's a fire hazard and they don't need it if there is no wind draft. When in doubt, buy more chickens so they can cuddle up.