Just hatched, they still have some nutrients from their yolk, so I wouldn't panic for the first 36 hours or so - just make sure they have clean water, not too deep, for drinking.
For food, I agree that while medicated feed - depending on a number of factors - may not be the biggest concern, lack of niacin can be very serious.
I found turkey/waterfowl crumbles, and added ground up rolled (not instant) oats one part to five of crumbles, with a tiny sprinkle of chick grit.
Some people report that a smaller amount of food, moistened, is more interesting to ducklings. Just get uneaten moistened food out of the brooder within a day, to avoid mold, which is another serious problem.