Place the chicken, chopped carrots, celery, onion, minced garlic, bay leaves, and thyme into the slow cooker.
Pour the chicken broth over all the ingredients, ensuring they are mostly submerged.
Cover the slow cooker and set it to low. Let it cook for 6 to 8 hours, or until the chicken is tender and shreds easily, and the vegetables are soft.
Once cooked, open the lid and use two forks to shred the chicken directly in the pot, allowing it to soak up the flavorful broth.
Taste the soup and add salt and pepper as needed. For a bright flavor, squeeze in a bit of lemon juice if desired.
Give the soup a gentle stir, then ladle into bowls and serve hot, enjoying the tender shredded chicken and fragrant broth.