We have had a number of ducks, mainly Muscovies, the drakes are large in this breed, and a few Aylesbury's,. We never had any fatalities but one duck did have a bad leg due to a drake. If you don't want ducklings then don't get a drake. They are messy and if you have a pond it will need a lot of cleaning. We still have two miniature mallards, no eggs any more, and I have to clean the pond filters every week.
Never had an issue keeping with Ducks and Chickens together.
There are quite a few facebook groups that put people together for rehoming of Chickens & Ducks, a quick search will find them for you.