I bought a few ducklings about 3 months ago and only 1 survived. She has been separated from my adult pair and I'm now trying to introduce her so she can stay in their coop and run. For at least a month she has been in a small fence in the yard that the adults roam during the day and at night she goes into a large crate for safety. During the day time the Drake spends a lot of time circling the fence. When we are in the yard we let the young female out with the adult ducks. The Drake sometimes chases her but has only caught her a couple times and bites her neck, one time pinning her down trying to mate. The young duck often runs toward one of us or the dog to get the Drake to back down. Recently we tried putting her in their run and the Drake was much more aggressive. My question is... Should I just let them work it out or wait until she is more mature and laying to put her in their run full time. He just seemed to be a lot tougher with the young female than he is with the adult female so I want to make sure I'm not setting her up for constant beatings or worse. They are different breeds and I'm not sure if that changes anything. I've attached pictures. Thanks!