Sorry, I'm a little late responding, but we don't have insulation. The coop is ship-lap pine so reasonable wind proof. There is a screen door that I put a sheet of lexan on for the winter and I close the screened windows. They were basically shut-ins for 2 months. There are 40 birds in there and they heat it a little. I believe they call it "frost bite" and not "cold bite" for a reason. Like us, the chickens feel a damp cold more than a dry cold so venilation is critical even more so in the cold. Comb and wattle damage is caused by too much moisture in the coop. My birds are going through 3 gallons of water a day which does end up on the floor or in the air.