Rinse chicken and pat dry with paper towels. Combine chicken, onion, celery, garlic, salt, pepper, poultry seasoning and thyme in a 3 1/2 quart slow cooker. Add chicken broth. Cover and cook on low 4 or 5 hours. Or until chicken is tender.
Remove chicken from slow cooker. Discard skins and bones; cut chicken into bite-sized pieces and set aside.
Turn control to HIGH. Dissolve cornstarch in cold water. Stir into juices in slow cooker. Cover and cook on HIGH 15 to 20 minutes or until slightly thickenend. Stir in chicken.
Meanwhile, cook noodles according to package directions and drain. Spoon mixture over cooked noodles. Sprinkle with chopped parsley.