She may be in shock after such an injury. They can make a recovery sometimes with awful looking wounds, and you should know if she is going to make it in the next 24 hours. Clean the wound with an antiseptic soap such as betadine, hibiclens , or just dish soap and water. Dry it a little so that you can see the damage. Apply neosporin or triple antibiotic ointment to keep it moist. If there is bleeding, apply gentle pressure. She needs to be left undisturbed with food and water. Scrambled egg, yogurt, and wet chicken feed might encourage her to eat. Don't try to stitch anything since it needs to heal from the inside out. If you notice any infection she may need an antibiotic, but for now just keep it clean and free of flies who will lay maggot larvae in it.