I had a drake that was overly aggressive with my chickens. He was hell bent on ... I'm not really sure what.
I thought the ducks weren't laying because they were too young, but as soon as he moved to a bigger duck farm with 12 girls (rather than 2) the girls started laying daily. My yard is much calmer. I tried for 3 months to figure out a way we could all live together but it made every animal on the property's life a struggle, just to work around one duck.
He wasn't cut out for small flock life. He is a stellar drake where he is now and, with a dozen ducks at his disposal, has not had the energy to terrorize her chickens at the new farm.
I am NOT suggesting you do the same thing, only telling you where I ended up after months of drake drama. You could try to add more ladies. I was trying to hold out until I got the new ducklings I ordered, but it will be months before they are even in with the flock and... well, it worked out for us all in the end.