Well if your coop is small enough you'll be able to keep them warm using their body heat. I only use a regular light bulb for egg laying in the winter (Hens need 12 hours of light per day for egg laying) and no heat at all. Living in upper Canada I get nasty winters with lows of -51 F! Your rock is going to be a chick when you get it? That means it will be fully established (Means at it's hardy age) in December! That could be late. I would use a heat lamp for the winter if you have chicks in it. Oh, I am soooo excited! My little cockerels are crowing! It's a little off the famous tune, but is getting better. Now it's week four for your chicks, hopefully they're going to be good little birds for you!