No, actually! Chicken is excellent protein for birds. When I cook chicken, I usually give a bit of it to my parrots as a treat. The breading isn’t necessarily the healthiest thing in the world (for humans or for ducks) but it’s not toxic. In small amounts, it won’t hurt them.
Chicken bones, however, should not be fed to any animal—including dogs or cats. They’re brittle and hollow, and can easily splinter and potentially pierce something in the digestive tract. (The ducks, however, probably avoided the bones in the first place, if there were any.)