yup! works fine but didnt last long and u need the submersable ones. ive used crockpots, heatlamps overhead. finnaly broke down and bought a plastic one. hard to fill as i have to turn it upsidedown . metal heater base the way to go. lightbulbs are cheap and auto off saves u money
It is available many places. It is built like a tank. Metal construction, metal shrouded power cord. I run an extension cord to the coop and plug this in. It cycles on and off by the temperature of the water.
I recall that some use light bulbs in flower pots and glass aquarium heaters, but I think this is more durable and possible safer.