I don't think the 12 volt will through enough heat from the bulb, but if it does, the battery wont last long.
Cookie tins are the way to go, they work and if you put them together right and use them inside your coop they should not give you any problems. Also with the switch socket you can just turn them off on warm days, or just pull the plug if you use a none switch socket.
I use a drill and push lightly but firmly to drill the holes for the socket and cord, then i take a file and file the edges nice and smooth in and around the holes..I also wrap a little electrical tape around the cord where it goes into the tin so the hole's edge does not rub through the cord after years of use.
The bulbs are 25 to 40 watt Candelabra bulbs and the socket is the same size as any light fix you have in the house, we use bulbs that fit into our chandelier type light over the dinning table.
One switch light socket, cost $4.25 at true value hardware
1 cookie tin about 2 bucks or less
1 8ft light duty extension cord 1.99 on sale at true value
1 40 watt bulb about buck or two
so about $10.00 to make one that works..
thats a deal and you can build 4-5 of them for the price of one that a feed store sells
Im sure if you do alot of yard sale hunting you can even build for less...
Charlie
