I have 3 Cayugas (9 weeks old) and 2 runners (about 10 weeks old I think). I was told I have 1 Cayuga male and the rest are females. The one that I'm pretty sure is the drake (he whistles and is bigger, his bill is wider, he's a bit more rough that everyone else when eating peas from my hand, etc) is just picking on one of my runners. It's a fairly new thing. I noticed a couple of feathers in the box they were living in but chalked it up to overcrowding while waiting for their house to come. Now the other day, I caught him pulling at the feathers on the back of her neck area. He was doing it in their little pool and then out while they were on the grass. Now I'm finding feathers in their new house. Is he getting "interested" already? I did a search on here and some people said their ducks lost feathers around this age and it has been hot here but even if the feather loss is normal he was definitely picking on this one runner the other day. My runners are my favorite, (there, I said it LOL) and I don't want him harassing them, he's SO much bigger than them.