Storey’s Guide to Raising Ducks says, “Commercially, Muscovy drakes are crossed on Pekin, Rouen, or other large ducks. These eggs hatch in 4 weeks, and both males and females are a similar size at butchering age. The hybrid females from this cross (Muscovy drake × Mallard-derivative duck) typically do not lay, and the males are usually sterile. The reciprocal cross of Mallard-derivative drake × Muscovy female produces offspring that take approximately 5 weeks to hatch and have considerable size difference between the sexes. The resulting hybrid females usually lay small eggs that do not hatch. Males from this cross are sometimes fertile.”
I hope that answers your question.