There are veterinarians who advocate pulling primary feathers to help damaged feather follicle growth. I have done numerous consultations with people whose Greys are completely phobic around them, but they behave normally with other people. And through guilt by association, their human owners must also be feared. Phobic parrots are the most heart rendering to deal with because their owners love them dearly, and much of the time, they have no idea why their parrots won't respond to their love. Believe me, it is much easier to prevent phobic behavior than to deal with it after it happens.
Parrots are prey animals by nature.
That means they react to danger with a flight response. In other words, they won't stick around to confront their enemies. Try to anticipate what may frighten your Grey. Sometimes it's as simple as a new toy or piece of furniture. Let the bird become familiar with the object from a distance over a few day period before placing it in or near the cage.