Spray the slow cooker with nonstick cooking spray.
Add the carrots, celery, onion, flour, chicken broth, thyme, and bay leaf. Stir to combine.
Place the chicken breasts on top and season with the salt and pepper.
Cover and cook on LOW for 4 to 6 hours or HIGH for 3 hours.
Remove and discard the bay leaf.
Remove the chicken, shred it with two forks, and return it to the slow cooker.
Stir in the frozen peas and heavy cream.
Cook for an additional 30 minutes.
Meanwhile, bake the refrigerated biscuits according to the package directions.
Ladle the chicken mixture into bowls and top each serving with a warm biscuit.