
5 gallon bucket outside, covered to protect from debris. 1 tblspn of ACV added per gallon of water to prevent algae buildup.
Gravity fed, and needs to be refilled monthly or so. Lots of info on this forum about how to do this.

Chickens are curious about the red nipple and will peck on it. When they do water comes out. They learn to use this very quickly.
NOTE: If a dish waterer is in they coop that will use that instead of the nipple system since they are hardwired to go to "pools"
of water. Simply remove the old waterer and they will go for the nipples, believe me. They DO NOT have to be trained.