Cleo, has a feather picking problem that I have been working on for awhile now, I've had him for about 12 years, very nice and gentle bird

Pookey, unpredictable personality, sometimes he'll be calm and nice and other times he may snap at you and give you a hard bite, I've had him for about 11 years......

If anybody has advice on a feather picking solution, I would greatly appreciate it, I've tried various sprays and supplements but nothing seems to be working