I should probably mention that those Muscovies were half feral anyway. They slept outdoors all year round - other than the one who terrorised me for a couple of months after she decided to nest and raise chicks in the polytunnel - in an area that for part of the year was only accessible to humans if you had a machete. Only feed they got was what they could steal from the chickens (who, in turn, terrorised the Muscovies despite being far smaller) and other animals or foraged for themselves either in nature or from the polytunnel and veg field. The adults were wild and the ducklings they raised were even wilder.
Muscovies that are actually kept as livestock by people who like their animals to be relatively tame might well be different.