I think we've decided to avoid messing with introducing them to the older birds. Since we're moving everyone to a better spot in the yard we've decided to build a duplex giving each flock their own space right next to each other. My only other concern is the new birds are straight run and judging by voice sexing I've got 3 of each. Is that ratio going to be ok for the girls to deal with? Or would we be better off combining them afterall so that we'd have 5 drakes to 11 ladies? I'm worried though that the crested and rouen drakes might be too large for my mallard girls? I'm not going to get my hubby to build me anymore coops, he's drawn the line and I don't blame him, so I need to get this right the first time hopefully.