Ming Mei and Victor are runners, about 8 months old now. We introduced them to baby ducks before, back in january when we got Sammy and Peter. They always ran away from the baby ducks when we presented them to them. When they started taking baths together, the big ducks were always super scared of the babies and swam away from them. When they were allowed to walk around the house together, Victor would chase little sammy, but Peter would step in as her body guard and chase Victor away. The big ducks were never mean or even tried to bite the babies... Then Peter and sammy went to go live at allaboutdemchicks place with her ducks since they were not suited to indoor life.... We decided to get two more runners, Vinny and Ollie, who are imprinted and suited to living inside. They are now about 7 months old. We decided they were big enough to start taking baths with the big ducks to get everyone acquainted. But we noticed a big difference.... The big ducks not only try to bite the babies, they chase them down and lunge after them. We used our method of disiplining them like we did when we taught ming mei not to bite victor. (ming mei is a couple weeks older than victor). But no matter what we try, them don't listen and keep chasing them. I diapered them and let them run around my studio, and again victor chases them, ming mei bites them... I noticed victor bites Vinny's neck... Any ideas what this behavior is? Why they do it? The babies are a little bit smaller than the older two, and they are almost fully feathered. I wondered about dominance but i am worried about someone getting hurt... Victor bites pretty hard making Vinny yelp in pain. Why would they not pick on the babies last time with peter and sammy, but this time they are extra mean to vinny and ollie? Funny thing is, the big ducks know they are not supposed to bite and they quickly learn what, "Shoo! Scram!" meant... (When i am shooing them away from the babies) When they are not supervised, they live in different pens. The big two have the big pen, and the little two are in their own brooders still. I'd like to move them to the big pen soon, but i am worried about this fighting... Supposedly they are all girls... the little one Ollie is the only questionable one.