I have only resorted to grabbing them by the legs if they are really mean or aggressive.
Once they are trance-like, I grab the wings to pin those down, flip the bird right side up & then tuck the birds' back under my right armpit, while keeping their feet in the other hand (left hand). I then use my right hand to cover their eyes. This usually makes them very calm.
Most of my birds I can just walk up to & pick up. With the exception of a few of my muscovies.
I have quite the technique, I know! LOL
As far as physically catching them, I usually wait until night time & then lock them into the coop. Then I can wait until it's really dark & go out with a box & lift them up & put them in the box.
Once they are trance-like, I grab the wings to pin those down, flip the bird right side up & then tuck the birds' back under my right armpit, while keeping their feet in the other hand (left hand). I then use my right hand to cover their eyes. This usually makes them very calm.
Most of my birds I can just walk up to & pick up. With the exception of a few of my muscovies.

I have quite the technique, I know! LOL
As far as physically catching them, I usually wait until night time & then lock them into the coop. Then I can wait until it's really dark & go out with a box & lift them up & put them in the box.