I am in southeast Michigan. I have 3 hens and a rooster, all Seramas (Belle, Rose, Mary and RooBoy). Like most, I wrap my roofed outside (6' x 18' x 6' tall) run in plastic and it provides nice "greenhouse" heat most days even when we are in the teens and low 20s. I had the inside of the coop wired last year so that I could use a heat emitter "bulb" (the ceramic kind that sheds no light, only heat), a daylight bulb for when it is below zero and the babies have to stay inside, and an additional reptile heat bulb for when the ceramic bulb can't heat enough. Since I have 4 bulb receptacles, these bulbs stay in place all the time. This has worked well for me, better than dealing with hanging lights with reflectors and switching bulbs. I have a thermometer in the coop so I can monitor the temp-- I keep it around 40-55 degrees so the water never freezes. I've tried timers in the past, but since I check on them in the morning and evening, I really like just being able to flip the necessary switches on or off. These are located right outside of the coop. My coop is on the small side, since I only have 4 bantams, 3' x 6' with part of this being 2 levels. It's insulated, utilizes double-pane windows for openings, and sits inside my garage. I keep my regular cleaning schedule for the coop during the winter: replacing shavings each week, cleaning and scraping the coop floors, treating with diatomaceous earth to kill mites, dusting the chickens as needed and often sanding their wood perches. Yes, my feathered "kids" are spoiled. They are my pets. I understand that with big flocks or non-pet chickens, folks might not be so concerned with making winter life so comfy.