mine were sharing temporarily but had no problems so theyre still together. that includes drakes and cockerals. but mine are all last years hatch so mite change when theyre older, wud def be ready to protect any young. we also have a lot of visiting pheasants which they all cope with. the ducks get the upper hand, but never seen them fight, plus they have quite a big area. a smaller area would intensify any hostilities. if they all have enough space, feed and water (give the chickens a waterhopper so it stays clean and the ducks a shallow bucket) they will be happier. chickens enjoy the pond just as the ducks as they find the worms etc. ducks are good at making mud tho.