That makes no sense at all.....you can hatch Duck and chicken eggs the same way in the same incubator on the same settings or hatch under a broody and she supplies the exact and proper heat and humidity to her eggs.....Ducks do not need water to hatch eggs.......
Cheers!
If you research it you will see that many people who hatch ducklings under a chicken will take a wet wash cloth and whip a little water on her breast for the extra humidity that duckling require.
I do not intend to make an argument out of this so if you disagree with me that is perfectly fine....
No harm, no fowl......Lots of ways to hatch eggs that work......
Cheers!