I have Khaki Campbells and Blue Swedish, as well as one runner. All of them have perfect feathering.... EXCEPT for a few of the female Campbells. What is up? They are all the same age, 10 weeks old(except the runner and one Campbell female which *does* have good feathers. These 2 are 3 weeks older) the feather loss is in the chest area. They are so young that their flight feathers are not in all the way yet, but all the other feathers look great. If they were lots older I would say it looks like a brood patch. I haven't seen the ducks be mean to each other. Any guesses? The only thing I saw is that the areas without feathers are about where the ducks rub against the side of their pond when then lean in to drink or jump in. But the pond is out of rubber, and doesn't seem rough at all, and the rest of the ducks seem fine.