We're in the mountains of SW Virginia. We had a recent cold snap into the mid-teens, not a lick of ice int heir waterer. That is with a 40w appliance bulb. If I see ice in the bowl I will up the wattage of the bulb little by little. I have to have the appliance bulbs around the house anyway! Hope that helps you out!Yes. That and my ducks tend to go thru at least 3 gallons water per day.
I'm glad you found a setup that works well for your flock. Where are you located? I ask bcz there are several folks in my state thread using a waterer like you've described.