I had a call pair in my flock with (at that time) 8 Cayugas and a whole lot of chickens. Plus a goose. Shortly after moving here, the call hen disappeared. After a while, the Cayugas ganged up on the call drake - he looked pretty ratty all the time. Then one day he just had enough of it and started chasing the Cayuga drakes, plus skuffling if the other drake(s) didnt get out of his way. Now there is only the "get out of my way" head-poke and they get along
Elvis has also taken a Cayuga wife. I call her Boudica, but deliberately mis-pronounce it "Boh-day-shah" because he thinks she's just bodacious as all get-out.
Anyway, a call duck pair would be good.