Place the chicken breasts at the bottom of the slow cooker and pour in the chicken broth.
Add the sliced carrots, celery, minced garlic, bay leaves, and sprinkle with dried thyme on top of the chicken and broth.
Cover the slow cooker and cook on low for 6-8 hours, until the chicken is tender and shreds easily, filling your house with a warm, savory aroma.
Once cooked, carefully remove the chicken breasts using tongs or a slotted spoon, then shred the meat with two forks and set aside.
Discard the bay leaves and return the shredded chicken to the slow cooker, stirring gently to combine.
Add the uncooked egg noodles into the broth, then turn the slow cooker to high and cook for about 20 minutes, until the noodles are tender and chewy.
During the last 5 minutes, stir in chopped parsley and a squeeze of lemon juice for brightness; season with salt and pepper to taste.
Once the noodles are cooked and the flavors meld together, give the soup a final stir and adjust seasoning if needed.
Ladle the hot soup into bowls, garnishing with extra parsley if desired. Serve immediately and enjoy the cozy, comforting flavors.