I need help to settle an argument with my husband. We live in North Carolina (not in the mountains). We have some cold nights in the winter, frequently in the 20s, occasionally lower. It rarely snows. Most days are in the 50s during the winter. We keep five hens in a chicken tractor in our backyard. They free-range some most days, and seem pretty content. The portion of the coop they roost in is a raised box about 4x4x3 with a sloping roof of currugated metal. The walls go right up to the roof, so ventilation is in the waves of the roof. We are arguing about whether or not to block off the door to the roost at night. One opinion is that wind coming in through the door to that small space is a dangerous draft for the birds. If we close it after they go to roost and open it at dawn, they will be sleeping the whole time, and will stay warmer. The other opinion is that closing the door diminishes ventilation too much. Predators have not been a concern. Locking the hens in a small space without food and water is risky, even if someone lets them out early in the morning. The opening is partially protected by another sloping roof. What say you experts? Should we be locking them in or not?