The one that hatched 12 was a first timer, barely a year old. She was taken by a predator just a couple of weeks ago.

we also lost 7 of the ducklings. (3 had already died due to cold or accidents within the first couple of weeks, so I only have 2 of those left)
She was sitting in a little log house inside my duck's pen. I never blocked her off until after the ducklings hatched, she could come and go as she pleased while incubating. Then I fenced off an area around the opening for about the first week and slowly let her introduce the others to her babies. She was a fierce momma!
The one that is due any time found a spot in my yard, behind my baby-chicken grow out coop. I'm figuring on doing the same for her. The third is between my fence and the young duck's swimming pool. They pick the oddest places!
But to answer your question... I would advise slow, supervised introductions. Drakes are unpredictable. They can be wonderful, or they can be brutal and want their girl back! Much depends on the rest of your flock dynamics.