Well, down to 2deg last night and I felt sorry for the girls. And it was very windy. 2 sex linked, 2 amerucana. So thinking on it, I realized a plate warmer would work, or a griddle that could be turned down really low. The coop is fairly air tight, and the opening is protected from direct wind. I found a Presto Griddle model 21-664 (Stock number 07074) on sale for $18 at Walmart. Last one on the shelf. 10x16inch cooking surface. Heat control, and it will go low enough you can hold your had on it. Perfect. Tonight is the first night of use. I have a wireless temp sensor in the coop so easy to tell how well it is working. I set it up in a corner with a floor tile on top, and on top of that a brick to keep the girls from knocking the tile off. It will absorb any excess heat and help distribute it a little.
It is under the roost and for now I had a couple large wood clamps on the roost to keep them from roosting directly over it for obvious reasons. It was about 35deg in the coop when I put it out there this afternoon and turned up the thermostat until the "on" light just came on. I checked it a couple hrs later and the light was off, but the tile was nice and warm. I think it will work perfect. The heating elements are inside a cast iron bottom so no exposed hot wires. If this works out I think I might look into installing vertically it on the back door, which is about 3x4ft and swings out. That would put it out of the way of the roost, off the floor obviously and away from dust, shavings, and of course poop. The roof slopes down towards the back, so the heat would rise and go towards the front, cool down, drop down and circulate back again.
Link to walmart showing the girddle http://www.walmart.com/ip/Presto-Cool-Touch-Electric-Griddle/3576547
