What I have found works is to sit as still as possible on ground in coop or yard for 15-20 minutes and talk quietly to them. Eventually, they get curious and you will observe them gravitating closer to you. They will hopefully come up to check you out. Now here is the key. Do NOT attempt to touch them, even if they nibble on you. Just talk to them. Do this once a day for a week straight.
Mine would do back flips for sweetcorn and the speed they get up when they hear their treat bowl getting topped up. I love my Muscovies such personalities they have.
