There are several threads on BYC about aspirin dosage for chickens. Just type it in the search window and it will pop up for you. One member was using 1/4 of baby aspirin on their chicken. That would be around 20 mg. I've always used 5 mg per pound of body weight for our dogs but I don't know if that holds true for chickens. I just gave our 40 pound dog a whole baby aspirin for leg pain from an old injury. That's under the recommended but it works. I always like to use the least amount of any pain killer that will give relief. Remember that aspirin is a blood thinner and any wounds new wounds will bleed a little more than normal.
As for ointments, triple antibiotic will work against bacteria but it has fallen out of favor by some due to the potential for it to promote fungal infections in an open wound. Believe it or not simple vasoline is being promoted as a wound salve, but given the nature of the wound your chook suffered, I'd slather her up with triple A and do what you can to keep the wound clean.
Yes, use extreme predjudice against any and all racoons and do it without a twinge of guilt.
Hope your girl gets to feeling better. That was a nasty wound.
