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With no electricity you might consider incorporating something like this. It's a rubber bowl I got from Tractor Supply. Since it is rubber it won't beak when the water in it freezes. Since it is black if you set it in the sun it acts as a solar heater and stays thawed a lot longer than things not in the sun. I used this in Arkansas where the overnight lows occasionally got below 0* F. You should see colder weather. In summer I used a white water bowl to keep it cooler.
The sun does not always shine, especially at night. Every morning I'd have to bang out the ice and refill it. Since they can and will poop in it I change the water every day anyway to keep it fresh. If the sun were shining brightly outside the water would stay thawed down into the teens. Cloudy days caused more problems.
I made that holder to keep them from tipping it over by standing on the edge and to raise it a bit so they scratch less trash and bedding in it. It was rare but occasionally it got wet enough that the bowl froze to the stand. That stand did not bang well, that created problems.
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I'll include this photo too. I took it when the temperature was 4* F. I leave the pop door open during the day and let them decide if they want to come out. Since a cold wind was not blowing they came out. You can see where I busted ice out of this in the mornings. It's up on the block to keep them from scratching trash in it. To keep them from tipping it over I'd put some large rocks in it. The problem with that is that the rocks get frozen in the block of ice. If they don't thaw during the day I could run out of rocks to use.
I'm not trying to say this is a perfect solution, winter is challenging. I've tried to mention some of the issues to maybe help you come up with a solution for your situation. Good luck!