Is it really necessary to insulate a coop? I have 6 chickens and live in MA where we have some really cold winters. The coop is made of 2x4 framing with plywood sheathing, 30# felt and clapboards. Do I really need to insulate it? I put some hay in there figuring they can nestle down in that to keep warm if needed. The floor is elevated and is plywood. I thought about adding some plywood to the bottom few feet on the interior side of the walls and figured I could pack the cavity with hay. Any problems with using hay for insualtion?