I find this interesting and that is why I asked...... separated out of view? We have had to pen up a duck to address a leg issue but never took her out of sight of the flock. So I really didn't see any changes after they were all together again.For a few day's, I would think. Look at the people that have to doctor up the sick or attacked chicken's in the house for a few day's, and then put them back in with the flock. It's like the flock doesn't remember who they are. I don't know if it work's with duck's too or not. I guess that you could ask over in the duck's thread.
I am still new and learning behaviors of both and very thankful not to have some of the issues other members post with their flocks either mixed or not. From my own personal experience with a mixed flock, unless a person has unlimited room for both to roam, IMO, separate coops would eliminate the little squabbles between to two.