I don't have any experience with males, but I have 3 adult ducks that I just introduced my 5 9-week old ducklings to. Do you have a yard or larger area you could put them in when they first meet? I would hesitate about putting them in a pen together at first as the older ducks may try to pick on the younger ones and could trap them and gang up on them. The first few meetings for our ducks were highly supervised, in an open area (the backyard that is fenced in). The older ducks were ready to establish pecking order right away and would chase the little ones if they got too close, and pull feathers out if they could catch them. I currently have them in side-by-side pens when they are locked up. They are getting used to being around each other, but I'm not comfortable leaving them alone together just yet. If I were you, I'd just take it slowly and don't get discouraged if it takes awhile for them all to warm up to each other. They will get there eventually. It's only been a week or so for ours and already they are getting more comfortable together.