How many chickens are going to be in the coop? We are in Maine and we don't heat our coop. It's insulated with foam insulation and there are 35 chickens out there - that many birds heat the coop just fine all winter. Mine also go outside all winter because we snow blow their yard for them, which I think makes them conditioned to the cold. I have single comb chickens (as well as pea combs and rose combs) and all survived nicely for the third winter in a row now.
I read that they are healthier with no heat and I am inclined to believe that based on our experience. I am always amazed to see them walking through the water out back when it's cold outside and it doesn't phase them in the least! Makes my feet cold just watching them.
They get spoiled with cracked corn all winter right before bedtime, too.
We ran an extension cord to our coop as well, but our lights are those pigtail fluorescents - so they are not getting any heat out of them.
I read that they are healthier with no heat and I am inclined to believe that based on our experience. I am always amazed to see them walking through the water out back when it's cold outside and it doesn't phase them in the least! Makes my feet cold just watching them.

They get spoiled with cracked corn all winter right before bedtime, too.
We ran an extension cord to our coop as well, but our lights are those pigtail fluorescents - so they are not getting any heat out of them.