Once you become a duck-keeper you'll know just why Donald Duck doesn't wear pants!
I found it easiest to keep ducklings in a plastic bin rather than a cardboard carton. I line the bottom with an old towel, and have several that can be rotated from the duck bin to the clothesline where it's hosed off & left to dry. The water is kept in a plastic tray (shoebox lid) to help contain the spillage, and kept at one end of the bin, the opposite side is raised a few inches to help keep the spillage on one side.
Here in South Florida I can put my ducklings OUTSIDE in the grass during the days as soon as they're a few weeks old (they still come in by nightfall) so they can splash & poop out there.
Ducklings and ducks =
I think they are medicinal too, I'm certain they lower my blood pressure. Enjoy yours!!!