How do chickens keep warm in winter?

Make a chicken nest for them with milk cartons. Spread a layer of newspaper inside first, and then spread some hay. This nest is warm and comfortable for chickens. Put it in a sunny place during the day and put it back in the house at night. Cover the box with a thick layer of cloth. However, it is still necessary to leave a gap for the chicken to breathe air. In fact, you can also punch a few holes in the box cover.