1. In a pot, warm oil over medium heat. Add garlic, onion, carrots and celery; season with salt. Cook, stirring, until soft, about 6 minutes.
2. Add broth, 8 cups water and chicken. Bring just to a boil. Reduce heat to medium-low; simmer until chicken is cooked through, about 20 minutes.
3. Remove chicken. Bring soup to a boil over medium-high heat. Add noodles; cook until tender, about 12 minutes. Remove skin and bone from chicken. Shred chicken; return to pot. Season soup with salt and pepper. Ladle into bowls and sprinkle with parsley.