They actually live in this coop with my chickens:
No added heat. I cover most of the front with clear plastic to keep drafts out, leaving plenty of ventilation. I have three gallon heated water buckets that they have for the wintertime. That's it! Everything else is done the same as the rest of the year. I do shovel their run for them, of course!
That's great! I have a shed for mine, but they do get heat lamps! I came home once last year to find mine had climbed the snow bank and were looking for the pond!!!!