I'm wondering if we made a mistake with the ducks we have. We have 4 males that started being very aggressive toward one another. They are approx. a year in age. So, I brought home 4 mature female ducks. There seems to be territorial thing and the groups stay on their own side of the pond. When a male does get close, he attacks a female and seems to bite her pretty hard until she gets away. Did I make a mistake thinking the males needed mates?