Hi Ken, Coming into this a little late but I'd like to share some of my own
experience. Get or build a mobile
shelter and an electric net. Put the net around the shelter and charge it with a
solar charger, or a battery powered charger where the battery could be changed each week. Now there is a roosting spot with protection from predators. Muscovies fly very well and will leave the fenced area during the day to forage. Mine do it all the time. Then, in the evening, they will return to roost for the night. You'll need to bond them to the shelter for a week or so first, like
chickens. The shelter and
fence can be rotated around to keep the
poop from building up in one spot.
Chickens will occasionally fly over the
fence, but then seem to have a difficult time figuring how to get back in. Not the brightest. I've been thinking, however, how to facilitate a "step" over the fence for the chicks, too. Maybe a perch or a ladder, say, 3 or 4 feet high that the chicks could climb and jump out, that would also give them a "target" to jump on to get back in. I don't know how high a predator can jump, but if it's only a dowel or something, will a fox try to jump on it? The birds would, though, and maybe get back in for the night. Also, once the preds learn what electricity feels like, they usually avoid the area altogether. You would need large breed
chickens to limit your hawk losses, since they like smaller birds. I don't have any problems with the ducks. Good luck!