Since you're already greasing them up with the Vick's, I don't feel bad suggesting this.
Recently I posted a home remedy for feather picking that really worked, but it left my Brahma hopelessly filthy, greasy dirty and it wouldn't wash out even with a full-on bath. But, the point is this remedy works.
The magic ingredient is Grape flavored Kool-aid. Mix an envelope of the powder with two tablespoons Vick's and spread it onto the area that's being picked.
The reason it works is because birds react to grape flavoring the way we mammals react to red pepper. When I first spread it onto my Brahma's bare throat, where she'd been picking out her own pin feathers as soon as they emerged for the past four months, she tasted it, and immediately tried to wipe her beak. She hasn't picked since. I also used it on the comb of another pullet who was besieged by her sisters trying to tear off her comb, making it a bloody mess. Again, instant success.
The turpentine oil in the Vick's also is a repellent, and mixed with the Grape Kool-aid, it appears to be a winner. Cheap too.