Where’s the Pics!!! 
Most of my chickens and ducks get along ok, but I have had roosters and drakes fight a little. I think it will depend on your own flock dynamics. You’ll just have to see how it goes.
But... I would recommend getting another duckling about the same age, if possible. Ducks can exist with chickens, but it would be happier with one of its own kind.
What breeds are they?

Most of my chickens and ducks get along ok, but I have had roosters and drakes fight a little. I think it will depend on your own flock dynamics. You’ll just have to see how it goes.
But... I would recommend getting another duckling about the same age, if possible. Ducks can exist with chickens, but it would be happier with one of its own kind.
What breeds are they?