I have a cut off gallon tea jug in the coop that I can check the level on from the house. It's small enough they don't climb in and dirty it up, large enough that it was enough for a day when they were smaller. And I built a 5 gallon waterer with a big flowerpot bowl for a basin, too narrow for a perch and potty session. Neither of mine are under perches, so they stay pretty clean. I can go 2 days sometimes without filling. I rinse out the basin on the 5 gallon when the bucket gets low enough to tip over. (there's a lid on my bucket, but the basin is deep and rounded, so when the bucket gets low, I can visibly see it from the house. It's at a 40 degree angle)