I'm working on my coop design and struggling a bit. From what I've read, having lots of sunlight in your coop is important to keep down bacterial growth and the more sunlight your chickens get, the higher in vitamin D the eggs are. We have a couple of old windows in our garage (very old, I doubt they were original on our 1900 house, but they do have the glass that has "pooled", gotten thicker at the lower part of the window). I was thinking of using them to save money, but then I know they will leak air and be cold in the winter. This is the second part of my problem. We live in Iowa, and it's below freezing here for about 3 months of the year, with temps frequently below 0 F. I have cold hardy breeds (Rhode Is Reds, Plymouth Rocks, and Buff Orpingtons), but I don't want the girls to be freezing out there. Anyway, I have some ideas I want to run by you experts here. Hopefully some of you in colder climates can help me out with the winterizing type issues. Is it wise to have a raised coop in a cold-winter climate? The coop design I'm liking would have about 2 feet beneath the floor, but I'm worried having that cold air underneath in the winter will make the coop get too cold. Should I just build it with the floor frame resting directly on the ground? I was thinking of using corrugated polycarbonate sheeting for the roof, like Suntuf, to increase the sun exposure in the coop, but I wonder if these would leach out the heat in the winter? I also wonder if they would make the coop too hot in the summer? Y'all have probably seen this solar heater (I found the link on this site, but I don't remember where) http://www.instructables.com/id/Solar-Heater/ I was thinking of putting this guy on the southside of my coop for the winter. My question is, and no one may know, but can I just install it over the windows? Will it still heat/convect effectively? Thanks for any help. We have our chicks now, so we really need to solidify our coop plans and get building!