I have recently came up with a solution that has solved the problem without electricity.
Chickens don't drink water at night, they roost and sleep.
I visit my chickens anyway every morning, so why not make the container easy to carry so I can take it in at night when it's below freezing?
If I take it in at night it's got to be clean.
My chickens will never drink dirty water again.
On really cold days I just simply replace the frozen container with a fresh one that has warm water in it a couple of times a day depending on how cold it is.
You can easily rig up a light bulb to warm it if you live in really cold climates.
I sell them at my farm blog for cheap....there's even a do it yourself kit.
http://www.waldeneffect.org/store/
Chickens don't drink water at night, they roost and sleep.
I visit my chickens anyway every morning, so why not make the container easy to carry so I can take it in at night when it's below freezing?
If I take it in at night it's got to be clean.
My chickens will never drink dirty water again.

On really cold days I just simply replace the frozen container with a fresh one that has warm water in it a couple of times a day depending on how cold it is.
You can easily rig up a light bulb to warm it if you live in really cold climates.
I sell them at my farm blog for cheap....there's even a do it yourself kit.
http://www.waldeneffect.org/store/