I've got a female and male pekin ducks which have turned roughly around four months. They've been ranging with my chickens since they were old enough to stay out side. Recently, they've been attacking my flock. Any time one of the girls walks by, one of them will start to shake their head and charge, pursue, and grab hold of the chickens feathers. I've heard that the drakes turn aggressive, but its not just the male. Are my ducks maturing or just turning into ********??