This will be my first winter with chickens. I have eight hens that are about 8 months old. I have my entire run and coop underneath a carport so rain and snow are not issues. My run is 8' x 15' and my coop is 4' deep x 8' long x 4' high. It is elevated so I can stand outside the coop and clean it. I have river sand in the run and in the coop so scooping poop is easy and I do it every day or every couple of days. Since the coop is under cover I did not put a solid roof on it but only hardware cloth. I also have a window on the long side about 2' long by 9" high and a window on one short side this is about 14" wide and 9" high. The winters here can get very cold...single digit cold. My question is, since I plan on covering the windows with plywood or plexi-glass, should I put a solid roof on the coop or leave it open for ventilation to reduce the chances of moisture accumulation and frost bite. The hen's heads are within a foot of the roof.