Those look really nice! The dalmations of the ducks. I wish we had a stream on our property, but we do have a "wet" area where water just pools. I am debating of putting the ducks there (once big enough) but on the other hand that's far from the chickens and the enclosed run.
I have yet to see an article on what ducks need for laying their eggs. ..
So far mine do not like anything I've provided for them to lay in, they make their own nests in the bedding on the floor and burry the eggs in it most of the time...