Usually 3-4 weeks after you take the ducklings, you'll see eggs again.
I had a hen hatch out 14. let her keep them for 5 days then took them away. She wandered around the yard, went in at night with the other ducks, then started a new nest about 2 1/2 weeks later. She's sitting on eggs full time again and I have no idea how many are under her!
Is your duck really skinny? If so, you may want to try to fatten her up a little before she starts laying again. Ducks that are broody then go broody a second time without much time inbetween can get extremely skinny. My girl, for some reason, is FAT FAT FAT so I didn't have to worry about it. But some of my other girls don't eat while brooding and get really thin and boney
