I'm in the throws of designing an economical coop for 3-5 chickens. I live in a cold climate (western North Dakota). The winters are mild for ND, but it is typical for the temperature to hover between -10 and +10 degrees F for a good three months out of the year. My question is, if a coop is constructed of at least 3/4-inch plywood, how essential is it still to insulate the coop? I've read info that it is essential, and I've also read examples of people in cold climates who have not insulated. So please tell me, actual cold-climate-living chicken keepers, what are your winter coop experiences?