Just be aware that ducks have a fondness for splashing water around, so they will tend to make things damper for the chucks
The original Khaki Campbell ducks were bred by a Mrs Campbell specifically so they could be run with chickens, they only need water deep enough to wash their eyes, but they still love a splash, as do all ducks.
These are my ducks - which I love - but they really only lay eggs from Feb to the moult, whereas a good commercial Khaki should be more productive. Mine don't
need a pond, but they do enjoy one