This is different from the usual 'drake vs chicken' thread, because it's not the drake doing the attacking. He ambles about peacefully, hardly giving a second look at anything except our dog who he loves to chase (she's terrified of him, even if she's 40 pounds bigger).
Instead, it's the females. Some of them. Two of our friendly, docile, quiet cayuga females have suddenly started jumping up and biting our hens and even roosters right on their tails, even taking a running start to do so. Fortunately there haven't been any fights because the chickens run away from the ducks (the ducks are fat, therefore, bigger).
They've never attacked the chickens before - at least, not the females. Except one of the females would protect herself if one of the hens went after her, but they never started it before. And the poor rooster was quite surprised when she took a big nip on his tail and took a few of his feathers out. They are eating whatever feathers they manage to pull out - perhaps they're doing it as a need for protein (from the feathers) as opposed to random aggression?
The drake, meanwhile, just sits right by and watches, then goes back to peacefully eating next to the other ducks and hens. Our pekin female, the sweetest, and gentlest duck we have, does not participate in the behaviour.
I have noticed every so often the drake (a cayuga male as well as the 5 cayuga females) will, when the pekin begs him to mate with her, nibble on her feathers and gently pull out some to eat them, then walk away leaving her laying there. Our ducks are fed a high protein feed, and we didn't have this problem last winter/spring with the same feed and same flock. Perhaps they're bored.
Any ideas? I suppose if no big fights come of it then it's not going to cause too many problems, except for the poor rooster's missing tail feathers.