First I would let him come out to step up rather than sticking your hand into the cage. He may be starting to feel at home and that cage is his territory. Yes lack of good undisturbed sleep can make them grumpy just like us. Greys do like things to stay as they are it can take some time to even introduce new toys some times. Give him some space and more things to do, things to shred, puzzle toys or try playing some games with him like Peek a boo with a piece of cloth or toss the ball. More spray baths would give some relief to the plucking. The Timneh that is suck a bad plucker he came to me a few months back with only head feathers is now growing our most of his body and tail feathers with three or more spray baths a day. It really does help them.