A lightbulb under a CLAY plant pot works just as well
Flip the pot upside down on the light and turn it sit the waterer on top of it and there you go one waterer heated up with no worry of short or fire just be sure to bury the wire so your girls don't peck at it.
Flip the pot upside down on the light and turn it sit the waterer on top of it and there you go one waterer heated up with no worry of short or fire just be sure to bury the wire so your girls don't peck at it.