I like your innovation! It's obviously not a bullet-proof solution, but looks to be buying you more time between water changes. I'd very much like some photos of this setup. You do a good job describing, but it would help to see what you're doing as well.
So what I deduce from this is that if the inside temp stays at 0 or above, it usually won't freeze. Utilizing this method saved you from hauling that bucket into the house on countless times when it was well below freezing in your coop, so I believe you've got yourself a winning idea here!
