Water in the winter?

[Island Mountain Farm]

Sometimes being on solar is not ideal. Alternative energy systems are great for everything but heating and/or applications that take a low amount of power over a continuous period. Heating water for livestock is a double whammy. Not only do I need to figure this out for the chickens, I've got sheep and Muscovy ducks to keep watered here in the northern latitudes.

Anybody who's conquered this issue and wants to share the secret would attain sainthood in my eyes.