I've found that you may need to lift up the waterer, place it on a sturdy stand, cinderblocks or something. that way their waddles can rest against the pan and not dip in. my husband made a stand, i'll try and find a photo or 2...Looks like some minor frostbite on Sentry's wattles. When things got real cold this week, I went to a rubber pan with bird bath heater in It. Guessing while we were gone he got them wet drinking. Maybe I'll go back to a quart waterer that I swap several times.
The pan hasn't frozen at all outside, but I don't like the frostbite.