I have had a deal of success with my muscovy, putting two temporary dog pens round my patio -- that gives me two "gates" to get in and out. I put large containers of tomato plants, peppers, and some flowering plants along the edge of the patio so that it doesn't look unsightly. Once or twice they get in -- when someone has left a gate open. Mine are domesticated [rescued feral muscovy] drakes and too heavy to fly. If you have juveniles and females, they might fly over such a barrier, but are unlikely to if you hose them down and never feed them near the patio. Muscovy are very friendly and nosy. They like you because you feed them, and want to come up to your house to see where you are and what you are doing!!