I've heard mixed reviews about ducks and chickens living together. I've seen it done and there didn't seem to be any problems. But I've heard stories about serious (fatal) aggression problems.
I think if you let them check each other out through some sort of barrier for a while it could...
I definitely second moving their pen around unless you give them a very large permanent pen or free range. My duck area has expanded more than once since I got them because they turned the smaller areas into a muddy mess very quickly (and maybe because I keep getting more ). Once thing I...