Place the trimmed chicken breasts at the bottom of a larger slow cooker.
Top with onion, carrots, celery, garlic, thyme, rosemary, bay leaf, salt, and pepper.
Add the chicken base on top and pour in the chicken broth. Gently stir to combine.
Cover and cook on LOW for 7-8 hours, or HIGH for 5 hours.
Remove chicken from the slow cooker to a large mixing bowl. Shred chicken.
If using sprigs of herbs, discard and remove the bay leaf.
Return the shredded chicken to the slow cooker.
Cook egg noodles separately until al dente according to package directions.
Add egg noodles to the soup and cook on LOW for 5 minutes to allow flavors to blend.
Serve garnished with minced fresh parsley and a sprinkle of black pepper.