I use a hot plate under a tin font. I tried the Farm innovations heated bucket last year, and two of the nipples dripped and I ended up with icy stalagmites in the coop. I have electric in the coop for the heater and lights, no issues with it.

Daily buckets of water might work for some, but when we get a few days in the minus 10 range, the heated base and font combo needs no attention.

I also put a light bulb fixture in a half a cement block with a metal plate over it that I drilled holes in. Use a 40watt
Incandescent [ pre LED ] Bulb
Put the Rubber pan on top. Light bulb alone keeps it un frozen.

My metal heat plate I bought burned out in 1 year and cost almost $60 bucks that's not acceptable

But the hanging red bulb ^^^is my 1st choice because it also gives the coop heat

What wattage red bulb are you using? 250?

I built a coup that helps keep the water thawed. 2x6 walls with 1x12 ship lap covered with tar paper and pole barn steel. 6" of glass in the walls and 9" in the ceiling. Windows on the south side. The inside is sheeted with ply wood. It has be -20 or colder for the water to freeze.

https://www.facebook.com/watch?v=505935854610495 - I think it's a good idea to use exterior components when you wire a chicken house, keep the wires all enclosed in conduit. Seems way safer with all the hay and dust, plus chickens and critters getting at the wiring.

Read title. "Unthawed" = frozen. Am I right?

That was intentional. Have a sense of humor! Like Coonman and vechile.