Best to go about it slow, if you can put the new ducks side by side with your older ones where they can see each other but can't touch. maybe a fence down the middle of you run. It take a while for ducks to get use to new ones they see them as trespassers. After a couple days when you can be with them let them all be together while you give them treats, something you know they will gobble up, that way they are together but distracted by the goodies. after a week or 2 they should become a flock may take longer though depending on the breed of duck and how many drakes to ducks you have, Amiga just went through this with her ducks so hopefully she'll be on to give you first hand advise.I got new ducks today. They are 6 months old and im trying to combine them with 4-5 year old ducks, is this impossible or not? they look like they are trying to mate when i introduce them.