I live in south east Tennessee. Our winter climates might be similar. It's possible for us to run an extension cord from our garage to a heated waterer in the run, and I did that for a winter or two. However, the last several winters, I haven't even bothered with heaters. I just go out in the morning and break the ice in the goats' buckets and run warm water over the frozen nipple waterers that the chickens use. It's almost never cold enough to refreeze during the day.
I would love to find a solar or battery powered water heater, but if they exist, I don't know of them.