Chop the carrots, celery, and onion. Mince the garlic.
Place chicken breasts, chopped vegetables, garlic, chicken broth, thyme, salt, and black pepper in the slow cooker. Stir gently.
Cover and cook on low for 6–7 hours or high for 3–4 hours, until chicken is fully cooked and tender.
Remove chicken breasts and shred with two forks. Return to slow cooker.
Stir in frozen peas and let warm through for a few minutes.
Open refrigerated biscuit dough and cut each biscuit into quarters.
Gently place biscuit pieces on top of simmering broth. Cover and cook 30–40 minutes, until dumplings are fully cooked and fluffy.
Spoon chicken, vegetables, and dumplings into bowls. Serve warm for a comforting, hearty meal.