1. Isolate chicken
2. Make sure she has as much food and water as she could possibly want within 5 feet of her.
3. Wash the wound with hot water and soap and gently pat dry
4. Flush the wound with hydrogen peroxide
5. If it continues to bleed, use styptic powder to stop it
6. Check the wound for infection 3 times a day
7. If infection sets in, clean the wound twice a day
8. If it is warm, and the chicken can't reach the wound, apply dressing to prevent flies from laying eggs in there
9. Keep her warm
10. If she is very valuable to you, take her to the nearest vet. If you need help finding one, tell me where you live, and I'll find one for you.