I think you can put them together if you first let them get used to each other on opposite sides of a fence, for at least 2 weeks. If they lay down near each other at the fence line, thats a good sign they will do fine together. You might have trouble if the drake is bigger than the ducks and mates with them though, so I dont really know! But I do know that there are people who have chickens, turkeys, ducks, geese, and guineas all together and they seem to have no problems. I however, keep my ducks and geese separate. I think now that they've seen each other through the fence for a couple of years, Im pretty sure they would do fine together, however, the grass that the geese have on their side of the fence would be no more if I let the ducks on it. And geese love to eat grass. And I am also concerned that my gander might try to mate with some of the ducks and they are a lot smaller than him, soooo...I keep them separate for me it works