To an 8 quart slow cooker add chicken breasts, onion, garlic, carrots, celery, followed by dried parsley, red pepper flakes, salt, and pepper. Add the broth.
Top with fresh rosemary, thyme, and bay leaves.
Cover and cook on low, 6 to 8 hours or on high for about 3 to 4 hours.
After that, discard the herbs and bay leaves. Taste and adjust for salt and pepper.
Remove chicken from the pot, place on a plate, and shred it with two forks.
Return it to the slow cooker and add the dry egg noodles.
Cover and cook on low until al dente, for about 30 minutes or on high for about 15 to 20 minutes.
Garnish with fresh parsley and serve.