Greetings! I have figured many ways to utilize solar energy, shed light etc. My only question is whether there is a solar water heater for the chickens water supply? I plan on using a rain barrel style PVC nipple system and I would think that the water in the pvc pipe would freeze pretty quickly (I live in NE Ohio). I would like some way to keep the water in the barrel warm. Any ideas? I've tried looking for solar pond heaters and bird bath heaters with no luck!