First off, I would separate your bleeding girl from everyone else. You can put her in a clean dog crate so the other girls can't get at her, because it's possible that they are picking at her bloody areas. I don't know enough about chickens to know right off what this could be, but it's quite possible that the back one started off as a small injury and the other girls pecked at it, making it bigger. I'm not sure about the area under the wing, though, that's a stumper.
Anyway--what you can do for the injuries is the flush the wound with betadine or some other antiseptic that is safe for chickens. In a pinch you could use hydrogen peroxide, but it's not the best thing because it can damage the tissue and hinder the healing process. Recently, I used HP to flush a wound on my cat the first time, then betadine every day after that.
Make sure to put food and clean water in the dog crate with the "hospitalized" chicken, and flush the wounds daily. As for what else you can put on the wounds, you could probably put some kind of animal safe antibiotic ointment, but often times you don't need to put anything, just allow it to heal uncovered.
I'm sure you'll get a lot more input on this, but this is what I would do for the time being. Hope it helps and good luck.
