Just another note on electrical wiring/ extension cords in or close to the coop: Mice and even squirrels have been known to nibble at electrical wiring. Possibly because they can be a little warm. They don't usually survive the first good bite but fires have started this way. I know I have way too much time to over think this, but my life seems to be ruled by "Murphy's Law." I will be looking into more solar options that don't involve electrical current or flames. Has anyone used hay bales in their larger coops for added warmth?
In order for solar to be of benefit, solar panels turn that energy from the sun into electricity, which travels through connected electrical wires. So, the danger of electrical wiring will still be there, and same precautions would need to be in place. For example using metal conduit pipe or similar protection against chewing or gnawing. Our heated dog bowl cord has a spiral wire around it, the entire length for protection, plus looks to have thicker insulation, in theory to stop the dog (at least) from chewing on the wire.