Hello, I have 5 chickens who are 10 months old. We put them outside in our chicken coop/run at 8 weeks old. All summer and fall, they learned how to push the clear 'doggie door' to get into the coop at night and out again in the morning. They have been laying one egg each a day since August. They are very happy, friendly girls! (No roosters) I clean the coop once a week and they have been free range in our backyard all day and early evening up until the first snowfall. (They won't even walk on the snow!) We did build them a big open playpen with a roof and covered the ground with straw for them to dig and play in and gave them a big batch of DE to take dust baths. In December, it got really cold at night (below freezing) and we put in a thermostatic-controlled heat lamp that is 75 watts. (It's really a lizard light) It comes on at 35 degrees and goes off at 45 degrees. The first couple of weeks the girls continued to put themselves to bed, but around December 15, we noticed when we were getting ready for bed at 11PM they were still in the run, just hanging out in the pitch dark. We started to stick them into the coop manually before we went to bed because it was getting pretty cold at night...15 degrees and colder. On December 19, we went on vacation until December 28. One of our neighbors came over to check on them, give them snacks, collect eggs, and refill their food and water. I cleaned the coop the day before we left. When I got home, I checked the coop and it was still clean! No poop inside at all! The run, on the other hand, was loaded with poop. I suspect that they didn't sleep in the coop at all while we were gone! While we were gone, it got very cold and we got about 3 feet of snow. (It snowed the entire time we were gone!) Since we got home, they still won't go in the coop at night and I have to go out and pick them up and stick them in the coop. I am very concerned because it's supposed to be -2 tonight ...will they ever start going back in the coop? Don't chickens get cold? I know they generate a lot of body heat, but this is crazy. I don't know what changed that they decided they don't like sleeping in their coop. They still go into the coop to lay in the nesting boxes. They are still laying an egg a day, each We also still open the run daily so they can hang out in the yard, but they don't like walking on the snow, so they pretty much hang out in the playpen in the sunny area.