Strange pale feathers on the wing
We have a female (unsexed) panama amazon who otherwise seems to be happy, eats well etc. For the past year, she has strange pale yellow wispy feathers growing in her right wing which get quite long until she pulls them out. The other wing is perfect. It started with just the one feather that would grow longer than all the other wing feathers until it fell out but now she seems to pull them out quite quickly. This has resulted with a wing that is quite bare, she seems to pull out her normal feathers on that wing too.
She is quite old, having had a number of owners before us so I first assumed that it might be a sign of old age but the bare wing is worrying me.
Could this be a disease or something lacking in her diet - has anyone seen this before? She has never flown whilst with us so I don't think the lack of wing feathers bothers her. I don't want to put her through stressful visits to an avian expert (they are quite far away from us) due to her age.
Thanks in advance.