If you have a pair or more of ducks, they will more than likely hang together & not pay much attention to the hens. If I do have a duck that tries to mount a chicken, I'll put them in time out for a half hour or so & that usually does the trick is no fun to watch your friends play outside while you're grounded in the pen I guess But it's fairly challenging for a duck to catch a chicken so i've always had plenty of time to catch the duck before the was an issue. It doesn't come up often & it's pretty easy to handle if it does, you just have to keep an eye out. Best luck with your flock, ducks are so hilariousI have chickens and ducks free ranging together. They sleep separate though. The ducks tend run the chickens off of the feed, but I feed in multiple locations so everybody at least gets some. The ducks also free range better than the chickens. I personally wouldn’t house ducks and chickens together in an enclosed coop/run, unless it was PLENTY oversized. I also believe the drakes will mount chickens during the breeding season and it’s not good for the chicken. I’ve only had them since March so I haven’t dealt with that yet, but am preparing for a full on separation if need be.