If is is only one chicken bleeding separate it from the rest of the flock. Chickens who see red/blood with peck that chicken to death. The best thing to do is go to your local Feed store and buy a repellent ( I think that is called) peck-no-more. Or I would go with a wound treatment spray called blu-kyote. It is blue and also will help heal the wound left by the pecking. Also if your chickens are Molting they are probably not eating and that is normal don't worry about that they will start eating after a couple of days.