We are in the process of building our coop. We live in Iowa, and winters here can get -20 degrees (that's with wind chill). Do you think it would be a good idea to insulate the walls of the coop? The chickens we are getting are listed as all weather birds, but I just wondered what your thoughts were on insulating the walls. We already have window on the North and East side of the coop, and if needed, I can make a screen door for the inside of the coop and leave the main door on the coop open for added air flow in the summer. It's the winter that is worrying me. Thanks for the input.