Once my four female Muscovy ducks matured they have not stopped fighting. Well, they'll stop for a couple weeks, but then they are back at it again, and now it doesn't matter if they are laying or guarding eggs or not. I posted about my Muscovies bullying each other a year ago (https://www.backyardchickens.com/threads/how-to-stop-muscovy-ducks-from-bullying-each-other.1642077/), but it has since gotten more intense (as evidenced by the photos). I am very close to culling at least the two meanest. Of course I don't want to - they are pets. But keeping four ducks in separate pens is not an option, and if no one else has any ideas on how to stop this I might just have to get rid of them. 
They are fed NatureWise All Flock pellets, have a 3' x 5.5' coop (only three are living in it now), a 3' pool, and water and supplement bowls in a large pasture with lots of grass and fruit trees.
They are fed NatureWise All Flock pellets, have a 3' x 5.5' coop (only three are living in it now), a 3' pool, and water and supplement bowls in a large pasture with lots of grass and fruit trees.
