I have taken a rubbermaid tote and cut down one side... I put foam used to insulate pipes over the edge that I cut down so it will be easy on their necks... then I put the cover on - I have two plastic buckets of water inside. They reach through the hole to get a drink and most of the water stays in the rubbermaid tote. This is the best that I have found for my adult ducks so far. Keeps the pen fairly dry.