Laying depends on many factors.
In ideal settings, it also depends on your location (climate, weather, etc)
Here in New England, muscovy ducks tend to start laying in March/April and will lay until October/November.
If you collect the eggs daily, they will lay anywhere from 4-7 eggs a week (zero to 1 egg a day) assuming they are 1-4 years old (they tend to lay less as they age once they reach peak age).
I have found that if I let them sit on their eggs, they will sit on and hatch anywhere from 5 eggs up to 30+ eggs (the more eggs they have in the nest, the harder it is for them to keep all eggs warm so you may have a bad hatch. If mine sit on more than 25 I take some away). If you have other ducks or chickens laying in her nest, and can't move her nest to a place where she won't be bothered, then mark the eggs that are hers and you want her to hatch. Then go in every day and take out the "new" eggs that the others add. That way she is only incubating her eggs and not everyone elses.
Also, I have found that once they hatch, I generally leave the ducklings with momma duck for 2-3 days. Then I take them away and put them in the brooder. They usually will lay eggs and set again depending on how late in the year it is.
I have 2 ducks that hatched clutches about 3 weeks ago. I took the ducklings on day 3. Both ducks have already made new nests and have started to set on them. So they usually will set again as long as you don't let them raise the ducklings. If you do, then they will take care of them until they are 2-3 months old. If it's early in the season, I've had ducks raise babies to 3 months, then leave them to start another nest. But not all will go back into broody mode.
