You might try watching the Captive Foraging
video by Dr Scott Echols. His theory is that one of the reasons birds pluck or "over preen" is that, in the wild, they spend their entire day either foraging, resting, or preening. If they don't have the foraging component in their lives, they tend to over-preen.
Although my U2, Snow White, doesn't have a plucking problem, and she's always been good about playing with toys, I've been trying to teach her to forage as well. I'm hoping to head off any future problems. Now, the only way she gets any nuts in her diet is through some type of foraging device. She still may be getting too many nuts in her diet, but at least she's working for them
I started out by wrapping half a walnut in plain copier paper, tying one end of a leather strap around it with a simple knot, and tying the other end around a bar in her cage. Then I tore the paper slightly, so she could see the nut in the paper. Then I started tying them up without tearing them. In later versions, I put the nut inside a 3 oz Dixie Cup before wrapping paper around it just to make it a little more difficult, and later I even doubled up the cups to make it a little more difficult to get to.
Recently, I've started rolling up a scrunched Dixie cup with a nut inside with colored copier paper, and scattering pine nuts through the paper as I roll it. Then I take two of those "clover leaf"-like plastic disks that I scavenge off her old toys, and I run a leather strap up the center holes. I separate the disks and then wrap the rolled-up paper around the center strap between the disks (and add another nut-laden Dixie cup to fill it out). Then I lace the disks back together with leather through the holes on the outside of the disks. This makes a very cheap hanging plastic foraging sandwich that takes her a couple of days to pull apart and get all the goodies.
Then I bought one of those "Jungle Talk" plastic foraging devices that are meant for treat sticks. Instead of using treat sticks, I shred colored copier paper and shove it in the tube with pine nuts scattered through the shredded paper. I intersperse the shredded paper with nut-laden dixie cups that pack the shredded paper to help keep it from just falling out. So far, this one has been lasting her a couple of days as well, but it's also a bit messy as some of the shredded paper invariably winds up on the floor outside the cage.
I have other foraging toys that I've purchased as well. As a matter of fact, just yesterday she finally
figured out how to get past the top of a hanging acrylic foraging toy in her cage and was rewarded with a Brazil Nut for her efforts
. That toy had been there for well over a month without her figuring it out.
I hope Dr. Echols' theory is correct, but regardless, the foraging devices definitely keep her busy.