I hand feed often and haven't had any trouble. But every duck and rooster is different.
My only trouble maker has been my Muscovy drake and when that started 8 yrs ago I came here for help and got it. He soon learned to respect me. But ever so often I have to remind him. I haven't actually had any aggressive ducks and only one rooster and he was a big Brahma roo and went on to freezer camp. I guess I have been blessed in that regard. Maybe
@WVduckchick has had this in her many Calls? Or
@Pyxis @casportpony[/USER] has many ducks also maybe she has advise.