perhaps a tiny sweater?...and no futher comment on the above post.
I was always worried about the chickens in the cold, I couldn't believe it when they would spend the day out in temps around 0 but I have seen when the get cold they DO come in.
My EE roo was particularly sensitive, he'd run in the coop and settle down into the bedding to warm up, then he'd run back out to check on his ladies.
If they have shelter they will use it if they need to. Even a couple of hay bales placed in a semicircle will do.