They're not as stupid as you think, Richard. They, like slaughtered pigs and cows, anticipate danger. They know they've in trouble the moment you approach and grab hold of them, and that causes the bird emotional pain, physical pain quite aside.

Tell you what. Let's chop your head off and see if it causes you any pain. We'll get a couple of big wrestlers to hold you down while the deed is done, and we'll use a large axe and do it in one clean stroke. You can tell us afterward whether it caused you any pain or not. ;-D If you remain silent, we'll assume you were "okay" with the whole thing, and suffered no pain, right?