I have a total of 10 adult ducks. 4 are pekins (2 male 2 female) 4 rouens (3 male 1 female) and a pair of cayugas. They all run together, but the cayugas stick together, period. If another male gets too close to the duck, she takes off running away as fast as she can. If one of the other males does catch her, then the cayuga drake comes running to save her. So they are certainly paired up, and they are the only ones that do this! Anyone else have naturally paired up ducks?