I'm new at this too. Currently I free range my eight muscovys, three male and five female. Right behind my cabin is a four acre wooded marsh/shallow pond with lots of tree stumps and fallen logs to rest on. Their house is right on the water's edge, and it seems the only ducks that I can bring in at night are the two members of the bachelor club. The others, especially the females, like to perch together on a log that extends over the pond . There seems to be too much for them to eat in the wild because they don't eat much of the cracked corn that is provided inside their house.
My thoughts are that when winter comes, they will come in to stay. At that point I'll be able to harvest any offspring. Meanwhile I will continue to feed them small amounts of cracked corn so they will identify the house as a source of food.
This is a pretty wild area up here in the Michigan UP. There are foxes, coyotes, wolves, bears, hawks, owls, pine martins, etc. all over the place. These ducks really want to be independent, and hopefullly their instincts will allow them to survive.