How much aggression is normal when introducing young ducks to older ones? We have two 5 month old mallards and two 6 week old welsh harlequins. They've been able to see each other for quite some time. When we let them out together the male mallard is very aggressive, chasing them with his head down and plucking out feathers. We separate them within a minute of this because the new ducks are terrified and we're afraid of them getting hurt. The mallards are also mating, so I'm sure that's not helping. Is he going to hurt them if he tries to mate? I'm new to ducks and figured, since they are flock animals, it wouldn't be a problem to introduce new ones. Should I just let them work it out? We can't keep them separated forever but it looks like he's trying to hurt them.