I have 2 (formerly 3) debeaked hens because that's the way they came when ordered as ready-to-lay pullets from the feedstore. (I probably should have known they'd come debeaked but what can I say, I didn't, but what was I going to do, refuse delivery?) They do okay as long as I exercise a little extra care in how I feed them.
However I would not buy another debeaked chicken and would =NEVER=EVER= have any debeaked at my request. Its ONLY purpose is to let them be kept in highly stressful conditions with less pecking at each other. It does NOT relieve the stress and crowding; it is just a 'band aid' over one of the symptoms. I guess if a factory farm is bound and determined to keep 'em in those conditions they probably better off debeaked than pecking each other to pieces but to me the solution is to give them enough space that they can be reasonably happy.
On a practical level, there is some evidence that it causes lasting pain (when done the way it is generally done commercially), and it certainly affects their ability to free-range.
JMHO,
Pat