1. In a 5-6 quart slow cooker, combine carrots, parsnips, onions, and celery.
2. Add chicken, garlic, thyme, sage, salt, and pepper.
3. Pour broth and sherry over chicken mixture in cooker.
4. Cover; cook on LOW for 7 hours or on HIGH for 3 hours.
5. Stir in noodles; increase setting to HIGH.
6. Cover and cook for 1 to 1 1/2 hours more until noodles are tender.
7. Transfer chicken to a cutting board.
8. Using two forks, coarsely shred chicken; discard bones.
9. Return chicken to slow cooker.
10. Turn off cooker; stir in peas; cover and let stand for 5 minutes.
11. Garnish with fresh sage leaves.