Hi, welcome to BYC!
Sorry you are having trouble. Plucking is a behavioral issue, usually associated with over crowding, boredom, or lack of protein in the diet. I would have to figure you are feeding meat birds at least 22% protein if not higher though? How old are they, how much room do they have, what are you feeding including treats and supplements? Are they under a light at night? When you say meat birds, what breed?
Also, red invites pecking.

Chicken dynamics can be brutal and result in cannibalism.

You might try applying some Blu Kote. It will hide any red, and it *might* have an antiseptic in it. I haven't yet used it.