Hi there! I've had some feather picking issues lately myself and ran the gambit of remedies. The birds getting picked in my situation are my Salmon Faverolles...their beards and muffs have now been picked clean off...I've been lucky so far in that there's been no blood.
Here's what I've tried:
Blu-Kote: since it was purple on top of white/pink...it DREW attention to the area. No good. Picking increased.
Rooster Booster anti-pick: Bought this then saw it had tea tree oil as an ingredient, which I was told can be somewhat toxic if ingested, which it would have been in my case since the feather-picker was eating the picked feathers.
Vick's baby-rub: a goopy mess, but no harmful ingredients and after applying it to what was left of the feathers in the area my girls were being picked, the picking seemed to slow down. Found that you really need to apply at least twice a day though, so the picker gets a bad taste in their mouth. After that, even the smell of it seems to turn them off.
I think my problem was a mix of a nutritional issues along with the SFs white pouffy beards looking so different (a.k.a delicious) to a couple of my other birds. Anyways...the advice I was given, that made the most sense to me, was to cover your bases nutritionally (I now believe in AviaCharge2000 as a GREAT supplement) while you try this and that to stop the behavior. Hopefully, you hit a solution in there somewhere!
Good luck
I know how frustrating it is to see this happening!!
PS - I should also say that I used the Blu-Kote when my Black Autralorp had her bum picked a bit and it did wonders...blended everything together for a perfect camouflage.