I have bought most the parts to try and make a bowl style waterer that cleans itself. I have the option of pressure or gravity. Currently I use nipples, and while they have worked well, they do leak, and when there is water from rain or other sources in a puddle, the chickens seem to really like it better. So, I am working to design a bowl with a drain in the bottom. I plan to use a sprinkler timer. The idea is to put one of the actuators on the drain, have it open each day and as it drains, the water will fill bak up by default, thus rinsing the bowl out. The hope is to not have to clean the bowl all that often. Anyone tried anything similar yet?