@saysfaa. Sounds very interesting. Could you provide a picture of this setup? Looking for options, outside of electric. Have you heard, we are expecting below average temps and above average snowfall? We might get our first snow, north of the cities in a week.I also live in the upper midwest. I use insulation. Specifically a 3-quart, stainless steel, vacuum sealed pail. Most people would use it as a wine cooler. It has worked well for five hens.
Filled with lukewarm water, it will go 12 hours at anything warmer than 15F. That is In the day when they are drinking from it.
I have played around with adding things to push that limit - longer time at those temps or that long at colder temps - but I don't really need to so haven't gotten serious about it yet.
The simplest way would be a piece of 2" foam insulation board under it. Or even wood. Mine has been on a cement block. I'll probably get around to at least that much this year. Maybe even a second layer of foam board with a hole cut out so the bucket can rest inside it and have more insulation up the sides. Or some such thing.
I'm also thinking of sinking a container of boiling hot water in the bottom of it, I've tried that a few times; it isn't as easy as I expected. It needs something small enough to fit in the ice bucket and a way to stay at the bottom of the bucket without taking too much volume from the water.
I've also though of making a partial lid of some sort.
Anyway, I think it can be made effective for 10 to 12 hours down to subzero temps. I'd have to try some adjustments to see about colder.