My husband built a chicken enclosure inside an existing old stone building. It was great for the chickens in the summer as it stayed cooler than outside and there are many windows. Now we are getting ready for our first winter as chicken owners. The main door is a bit warped so some air does get in around it. I am trying to figure out if we should rebuild it. Do I really need to? It gets pretty cold here in the winter average 15 - 20 at night, not including the wind chill. I have two large windows and one small which are covered with one layer of plywood, the rest are glass but they face mostly east and southeast. The main door faces east. Has anyone ever kept chickens in stone buildings in the winter? Do I need to insulate or add plastic on my plywood covered windows? Thanks for your help!