I'm confused. I'm aware that I must have ventilation, however, I also read that I can not have any drafts. How can this be? Don't the ventilation itself cause draft? My coop was built from a shed. I intend on cutting some ventilation into the walls, however, discovered that it's double walled, so need to plan this out before cutting. Nonetheless, aware that they need ventilation, I cut the door. I cut off the bottom so they can come in and out. I also cut off the top and put in a screen so air can get it/go out. At night I nail a board over the hole at the bottom. Is the open screen up top a draft? If I make a row of hole saw holes all the way around 3 sides, is this drafty, or ventilation. Sorry, but I'm confused as to what's considered draft and don't understand having ventilation but no draft.