I have two chickens who live in a repurposed bunny hutch (about 2.5 by 5 feet) and have access to a fairly roomy run (about 100 square feet). Because of the lack of predators here in suburban Maryland and because my (enclosed) run is fairly secure, I usually leave the door of the chickens' house open at all times, so they can come out into the run as early in the morning as they want to. It's not very cold here yet -- when it gets cold and windy, I shut the door to the run at night. But I wonder, it's not like that keeps them any warmer, right? Does anyone think there's any sense to this? I want my chickens to be comfortable, but I'm not sure closing their door helps them. What do y'all think?