Welcome to BYC! Glad you decided to join our flock. The webbed feet of ducks are better designed for swimming than for running around on dry ground. This can certainly make them appear to be clumsy compared to chickens. Please feel free to ask any other questions you may have. We are here to help in any way we can. Good luck with your ducks.
Well ducks waddle from side to side thanks to their webbed feet. They always look comical on ground and full of grace on the water. Do you mean clumsy, like falling over or tripping over their feet.
Otherwise they sound just like ducks. You might want to check out the duck thread in the Other Backyard Poultry forum
I don't keep ducks, so I can't tell you for sure. If you think there might be something wrong with your birds, you can post this question in our Ducks section for more help for those Duck experts...https://www.backyardchickens.com/f/42/ducks