Even though i didnt have any issues with water freezing in the 5 gallon buckets i have now upgraded to 55 gallon barrels using the same cups just more of them in preparation of having surgery and not going to be able to walk for 2 weeks so far even though its been below freezing a few nights in...
The cups only get water in them when the chickens peck the yellow stem in the center so there really isn't but a drop or 2 in them the rest of the time
I used the water cups that they peck when they want water. the ones i ordered didn't come with rubber washer or nuts but i got those at my hardware store. Here is a picture of them
I have the same issue with not being able to get power to the coop but so far my auto water made from a 5 gallon bucket hasn't frozen. I am also in NC.