I have a friend that has a huge coop, they built a run off the front and I think they only did plastic on the outside on like 3 sides to keep the snow from piling up and wind off their chickens.
Mine live in stalls for the winter, in a barn, so I put plastic up, top to bottom, with a vent section farthest away from the open door, and on the other side, in another stall, away from the more open windows.
pine shavings, and then where they roost, it has wood on top and will be covered on two sides by a mattress cover. They also have a dog kennel (plastic) in their roosting area, that has hay in it, they mostly sleep on top and lay eggs IN it..
We do not use lights or de-icer's for their water, my barn owner gives them warm water twice a day. We have never lost a chicken.
Carol