I always leave a light on in the small chicken tractor when it gets less than 40 or so. But I'm wondering if this is necessary. I know lots of people have chickens in the North where it gets a lot colder than that. I'm in NC. And do they need to stay inside the coop all day if it's in the 20's or 30's? The reason I'm asking is bc the coop is really small, so I let them out into the large run. When it's rainy, I put a covering on it. Thanks in advance!