Place the chicken breasts into the bottom of a large slow cooker (I used an 8-quart slow cooker). Sprinkle the salt and pepper over the chicken.
Add the onion, carrots, and celery on top. Pour the chicken stock on top. Place the cooker on low for 4 hours or high for 3 hours.
Shred the chicken and add it back to the pot.
Taste and adjust seasoning if necessary.
Break the dumplings into thirds and add them one at a time to the pot.
Stir them in after every 5 or so dumplings you add in.
Place the cooker on high and cook an additional 1 to 1 and ½ hours, stirring every 15 minutes, this will help prevent the dumplings from sticking together and sticking to the pot.
It is ready when the dumplings are tender, puffed up, and the broth is thickened.
Garnish with fresh chopped parsley, optional.
ENJOY!