I built my coop this past summer and it has been working out great for my girls. it is Basic rectangle flat top roof design that is 4x8 and is about 4 feet high in the front and 3 feet high in the back. I put vents that I can open on each end of the coop to get cross ventilation. One vent is over the covered nesting boxes and the other is directly in front of the roosts. I also add DE to there bedding to help keep things dry. Since the weather has turned colder I have been closing both the vents. When I open the coop in the morning there a a build up of moisture from the birds breath and poop. I am afraid if I leave the vents open, particularly the one in from of the roost, that it will make the coop to drafty with the cross ventilation. I was thinking that if I add a roof vent that would be open all the time it would release the moisture and keep the coop dry. What does everyone think? Will something like this help or hinder?