Here’s a picture:Can you show me a pic? Sounds like a great idea.
The leaves make it hard to see, but the bowl is up on a short log like the one the pullet is standing on. There’s another log lying sideways in front of it, which in addition to being a step, also stands in the way so they can’t dig and scratch too close to the bowl and kick crap into the water. That, plus the elevation, keep the water clean.
I wouldn’t put water inside the coop, especially an open waterer like this. The evaporation will raise the humidity in the coop, raising the risk of frostbite when that humidity condenses and freezes on the chickens’ fleshy bits. I also wouldn’t want anybody stepping or falling into the water and getting themselves and the bedding wet. Outside, there’s more room, and they go into that corner only to drink, so they don’t step into the water at all. But the coop is smaller than the run, and even with ample space, they still manage to step in and on everything, in their shuffle on/off the roosts, the nesting boxes, etc. So my waterer stays outside year round, there’s no water inside the coop.