OK, something very strange is happening to our black female Cayuga. At least we were pretty sure she was a Cayuga until several weeks ago. I started noticing a couple of white feathers showing up on her breast feathers. Now they are spreading all over. It's like she's become one of those rare Koi fish that change their colors overnight. We also have a black female Indian Runner, and they are BFFs, and have even displayed homosexual mating behavior. I've also noticed recently that they have duck mites. Could this odd change in feather color be due to stress from duck mites? This is our first time keeping ducks, and we've had this pair for about a year (adopted full grown), so I have no prior experience to tell me if this sort of thing is normal, or if there is something seriously wrong with this duck.