Schlepp...the product is bitter apple or something like that. Doesn't work and can make them pluck more.
There are lots of products that supposedly help pluckers....I found a pair of lovebirds recently, one of which was self-mutilating. For the wounds, the vet gave me flamazine which has been working wonders...it is a topical anti-bacterial med. But, if yours is a plucking issue, I have heard you can try many things.
Some have had success with Pluck-No-More....it is a topical, homeopathic spray...but is is VERY expensive and the jury is out as to whether it works...there are other products out there that PLM supposedly copied....I think They are by BIo-King and called Stress no More or something like that.
Anyhow....not recommending them because I'm not so sure they work and you might be spending a lot of money for nothing. Maybe others can weigh in their success or lack thereof.
Now, with my lovie, I have noticed a MAJOR difference in her plucking issue since I started taking care of her. The mutilation was my biggest worry, but that seems to be easing and healing nicely. The plucking is better as well...she had plucked her upper left back, middle back, under the wing, chest and left leg. Every once in a while, I'll see a feather on the ground, but changes in her environment, diet and cage/toys has made a remarkable difference.
The advice I have heard is essentially this: Change the environment. If the cage is in a high traffic area, perhaps the bird is too stressed by the noise and needs more calm...Try moving it to a different area of the house..or even a different area of the room....perhaps put it near a window so it can look out. I change the toys and perches around in my lovebirds cage quite frequently so they always have a "new" home to explore. Add some veggies high in calcium and Vit.A....The dark, leafy greens like kale, swiss chard, spinach.etc are fabulous.
I also started to mist my bird daily with warm water and aloe juice. You can buy the pure stuff in a health food store....do not get the gel because it isn't pure as it has the thickening agent. You can also order "george's aloe spray" if you can't be bothered mixing the juice and water although the former is probably more economical. Aloe is a great soother and since the new feathers coming in are often itchy, the aloe and water or even plain warm water misted daily ( if you forget the aloe...not a big deal) is very beneficial towards helping keep the skin moist and less itchy and , therefore, they won't be tempted to pluck the new feathers.
I also read that putting in lots of chewy, rip-up toys is good. One site recommended a feather. So, I went out and got a natural, non-dyed feather...it was a cat toy. I hung it up and the birds love it...They often preen the feather which is supposed to be good because it takes the emphasis away from self-preening.
I have heard, however, that spraying them with water when they pluck isn't always a good idea because although it might look to us like we are distracting them, we are actually reinforcing the bad behaviour because it is getting a response. We should, supposedly, ignore the plucking when we see it....
As for the cone around the neck. That is, in my mind and in the mind of my vet, a last resort for severe self-mutilators. It is extremely stressful on the bird because it impedes their normal behaviour...ie: Preening. I would try the environmental/diet/watering approach first of all.
Something is obviously troubling your little fellow and it's frustrating because he gets lots of love from you. Unfortunately, he can't tell you so it's up to you to figure it out.
Quick question: even though he is out frequently, is his cage large enough for his size? It is still their refuge/security/home and it needs to be spacious and have lots of toys inside for them to play with.
Hope this helps somewhat...keep us posted. If none of this works ( with time...obviously...there are no overnight miracles) then medical tests might be in order. Some pluckers never stop...it becomes habit. Some seem to make a full recovery and then their owners wake up one morning to find every feather on the floor of the cage. Some recover and never pluck again. All you can do is try your best to make your GCC feel better.