we have an open coop/run with no walls, only a roof over half, which is great for because of the humidity here in the summer. In the winter, we are making bales of pine straw and stacking them around the walls of the run, and we use the DLM in the fall till spring, which add a lil heat for the girls.
I've read alot of posts from people saying you don't need to insulate for various reasons but certainly it depends on where you live. We get -40s here some months so feathers or not I'd have chicken-cicles if I don't insulate. 4 bantams will not generate enough heat to survive.
I'm insulating my coop with rigid dow foam to R12 and venting in a few areas. I'll have some pics up by end of weekend.
We are in south-eastern PA, and we just went to Home Depot on Labor Day and bought the insulation for our coop. We got semi-rigid pink foam and will cover it with panelling or masonite. Evidently, chickens don't care that styrofoam is not meant for consumption. We will be insulating the floor,(from below), the ceiling, and the walls of their quarters. Still pondering how to do the plexiglass windows...putting anything on the inside will be accessible to those "picky" girls. Maybe sandwiching bubble wrap between the window and another piece of plexi? Still thinking on that one.
I'm in SE PA & my chickens have been fine for 18 years without insulation. Coldest it ever was, was the first winter with a week of -22 at night. It is normally 0-32 at night, but we have horrendous wind in Breezy corner all winter. Have had many breeds of chickens over the years including bantams & have never had a problem. My coop is draft free. I do use a water warmer, but other than that they are on their own.
I don't insulate, but do cover the run with plastic to keep the wet and wind out and add a deep layer of straw in the coop. The birds really do adapt to the cold, even my little silkies! I only chose breeds that were listed as winter hardy of course.
[http://www.kittycooks.com/how-to-winterize-your-chicken-coop.html]How to winterize your chicken coop[/url]
In the old days, here in New England, winters were colder than they are now. A century ago those who wanted to keep some birds through a winter simply used thick layers of hay in the henhouse to over winter their birds.