My 2 Scovies have a pen about 10' x 16' with welded wire all around. It's 6 feet tall with welded wire fencing covering the top. I have a BIG sturdy doghouse somebody gave me as their house, and a big ladder made of branches for roosting (seldom used). Mine use their shelter when it starts to get dark and definitely in nasty weather, even though there is a lame tarp covering part of the pen. They're definitely more inclined to get cozy inside than the crazy 3 Pekins in the adjacent pen, who would barely go in their houses during the howling blizzards this winter.
My female sits in the far corner of the house and chirps at me when I walk by. I really have to put a door in the back of their house so I don't have to keep kneeling in duck yuck to reach for her eggs. I have a giant rubber food bowl about 20" in diameter and maybe 8-10" deep they occasionally bathe in. I thought in winter I could crack the ice, but it froze all the way down overnight so I got a floating pond de-icer. I also have another rubber bucket for water.
All the ducks get daily supervised free range time, but the muscovies take their time leaving the pen. I swear the Pekins are spring loaded when I open the door to their pen.
My muscovy drake is not to be trusted around me chickens. He used to try to mate some of the bigger hens, which could kill them. Now he is constantly attacking one my the roosters. Your mileage may vary however; my drake was raised with chickens and seems to have identity issues (I am actually his favorite hen-he has no interest in doing duck things but will stand my me wherever I go, nipping at my legs)