She will leave when she feels the hatch is over. If you provide food and water for her and the ducklings within a few feet of her nest she may stay longer until the rest hatch but it's no guarantee. Those duckings that first hatch have to eat/drink within 3 days & momma knows that.
Watch her & play it by ear..... so to speak...
Try the above or ...
You could take the first that hatch and brood them yourself to see if she will stay on the nest for the rest then add the first hatchings back & see if she will accept them. If she doesn't accept them back you'll have to brood them for awhile until you're ready to integrate them as a flock.
You could candle the later eggs to see how far along they have developed and make a decision fm there.
Watch her & play it by ear..... so to speak...
Try the above or ...
You could take the first that hatch and brood them yourself to see if she will stay on the nest for the rest then add the first hatchings back & see if she will accept them. If she doesn't accept them back you'll have to brood them for awhile until you're ready to integrate them as a flock.
You could candle the later eggs to see how far along they have developed and make a decision fm there.

