When we lived on a farm 1991-2007 we had some Kyuga ducks. Very attractive, and good layers. Unfortunately, even though had very good housing, they refused to sit on the eggs. An old farmer suggested that we put the eggs in with a broody hen, which he just happened to have, and these are some shots of the result. A dozen eggs, and they all hatched.
Some of the adult ducks who laid the eggs.
The old hen with her baby ducklings, which she dearly loved and wouldn't believe they weren't chicks.
The growing ducks. All of them survived.
One big problem that we had, is that ducklings get waterproofed by snuggling under their mother. The old hen couldn't do that, so when they eventually went into the pond, they nearly sunk without trace. We were forewarned of this, so we stood by with fishing nets and hauled them out if they got into trouble. After a while, they developed their own waterproofing, and all was well.
Den.