if not too late...

don't have to separate if you have a large enough pen

drake shouldn't attack them, but be on guard for possibility

our experience is those eggs hatch on the morning of the 28th day of incubating

mother duck hen is efficient and will stay on the nest with the ducklings until the last one is hatched or if separated by more than 24 hours will take off the ducklings and leave any eggs on the nest.

Make sure if ducklings have access to water they also have a ramp so they can climb out. The adult ducks won't help them and their shorter legs don't either. It is easier for them to enter than get out.

Improvise with what you have making sure that it's not a slick surface. Blocks of wood screwed or nailed together on either side of the pool like a step up & over & down work as does wire covered wood ramps. Wet wood is slick for them and slimes up quickly in a duck environment. Watch out for sharp wire edges that could injure them.

Fluffy down isn't as efficient as preened adult feathers, so they will get wet and need to dry off.