Sounds like either they or some other chicken plucked those feathers. If they were blood feathers, you may have trouble getting the bleeding to stop. If so, get a tube of Krazy Glue or Super Glue and a couple of gauze pads or cotton balls. Use the gauze or cotton balls to dab at the wound to remove the blood and then quickly put a drop of super glue on the feather follicle where the blood is. The glue won't work if it's really wet with blood, so try to get it as dry as possible before applying the glue. Do that for every spot that is bleeding. The glue will eventually loosen and fall off the skin. You don't need to remove it. Careful you don't glue yourself to your bird, but if you do you can use fingernail polish remover (acetone) to get yourself loose.
Did you know that Super Glue was invented for use in surgery as an alternative to sutures for closing incisions? Safe for humans, safe for animals.
