Cordless Heated Waterer Recommendations?

[Callduckies]

Does anyone know of any good cordless heated waterers that would work for ducks? It has to be able to survive Wisconsin winters (potentially -40° temps). I'm going need to move my ducks to an area too far from my house and garage to plug in my current heated waterer.

 

[thecatumbrella]

At those temps, most things will freeze. Even my heated waterer from Premier 1 is only rated to -20. I would just plan on frequent water changes on the coldest days, hopefully with something that’s easy to carry back and forth.

Didn’t realize how cold you guys got over there!