We have been bitter cold here, but sunny. - 30 degrees. When I first started with my chickens I put an old black plastic box that used to fit inside a pick up bed. I turned it on its side, and propped the doors open, instant sun porch and wind break. Well three days ago, I found an old window, about the same size and I propped it up in front of the doors. It is surprisingly warmer inside there. The girls love it. Mrs.K