I, too, am in the foothills of NC and will not be adding supplemental heat. I will be placing small aquarium heaters into their large bucket/nipple waterers, mostly for my convenience. Nature knows best. I will be covering 3 sides of my open coop with empty feed bags.
I'm going to insulate my coop because we are going to put an automatic drinker in there and it will surely freeze if we don't. I'll be putting a couple heat lamps over the drinker and a couple over the roosting area. Chickens may have feathers but the last 2 winters my roosters got frostbite pretty bad on their combs, the hens even got some. It has to hurt and don't make sense for them to suffer if they don't have to. We are going to start raising breeds with rose combs so our birds won't have to deal with that in the winter.
I am on the shores of Lake Ontario in Upstate NY...I bring the chickens into an unheated garage as it we would likely lose the coop in the snow. It is not unusual to get over three hundred inches of snow per year here.