I apologize in advance for what is going to be a lengthy post, chock full o' rambling... I own a cockatoo (living with my brother currently in the U.S.), several cockatiels (my sister stole them), and here I have a young African Grey and another cockatiel. So, yeah, I'm a bird nerd.
There is an excellent book out there, called "The Owner's Guide to Parrot Behavior", by Mattie Sue Athan. Ms. Athan is like the horse whisperer for birds. It's an excellent guide if you have a parrot with behavior problems, or you have a new bird, and you're not quite sure what to do...
To Tir: Your bird no longer has a cage-mate, correct? Depending on the type of bird, age, health, and damage done, the feathers can take a long time to grow back (I had a cockatiel whose entire tail had been lovingly removed, it took her 15 months to re-grow those feathers). Sometimes the feathers never grow back, but... with good nutrition, your bird might be able to recover some more of those missing feathers.
For any type of parrot or parrotlet, a pelleted food should be the basis of the diet, with a variety of fruits, nuts, veggies, grains thrown in for variety. Somewhere, I have a list of safe fruits and veggies for birds, if you want to email me a
kbarlau@hotmail.com, I'll dig it out, re-type it for you. Birds can eat anything EXCEPT DAIRY, but just like humans, should avoid things with a lot of fat, salt, sugar, overprocessed, etc. (our African Grey likes pasta, salad veggies, grapes, and chocolate chip cookies, but I always dig the chips out first.. and I've never seen a bird that didn't absolutely adore Doritos, just don't give him too many!)
I've found that overall, Roudybush makes the very best pelleted bird food, and I've always fed it to my birds back in the States. Now I'm overseas, and I haven't found anyone who sells it, so I feed my birds here LaFaeber's, which is also an excellent bird food. Zupreem is good, too, although I've had birds nitpick over the different colors, and wound up throwing away a lot of it.
Places like PetSmart usually carry at least one good line of pelleted bird food. If there isn't a store in your area, they are online, and you can order through them. If you're interested in RoudyBush products, they have a U.S. number, 1-800-326-1726
If you do switch foods, be sure and do it gradually. That's really important, as I learned from experience - some birds will get all suspicious and starve themselves before they'll touch new stuff.
Back to your poor parrot... if he's picking his own feathers, that's a whole different story, email me and we'll talk

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