The correct way to hold and handle ducks - especially Muscovy.

Cayuga, Muscovy, Runner ducks, Welsh Harlequin, Pekin... you name it. All ducks, Geese, and waterfowl can and should be held this way to prevent injury.

Chickens can be held this way too, to prevent wing beating.

This does NOT hurt the bird.
These birds use their wings to fly, which support their body weight.
Holding them by their wing bones is doing exactly the same thing - Supporting their body weight.