They certainly can, and a duck trying to mate a chicken can seriously injure or kill it, because chickens dont have the correct anatomy to mate with a duck. If you want to keep ducks and chickens together you'd want to stick to all female ducks (and they might still pick on the chickens - it depends on their personalities at that point)
It's also a bad idea to keep just one female duck with a male duck - domestics dont often "pair bond" and he can overmate and hurt/kill her as well. 4+ females per male is a common suggestion.
I personally wouldn't get Calls for a Pekin because of their size difference as well - you might struggle to integrate the new duck(s) and if your Pekin decided to be a bully the Call would be at a disadvantage. I'd go with another female duck or two in her weight class. She also might quiet down a bit once she's got appropriate friends with her. My two were mostly silent except for when they knew I was bringing treats or when something scared them.
