We don't keep ducks because of what they do to clean water and then the chickens will come and drink it - yuck - so we don't keep ducks. I think ducks like to mess up clean water to get algae and pond scum to build up so they can dive for the yucky stuff - it's what ducks do. I wouldn't keep them mixed with any other fowl except maybe geese. Ducks and geese are cute and the geese are great watchdogs but they need lots of water and space.