Place the chicken thighs, chicken broth, cream of chicken soup, carrots, celery, onion, garlic, thyme, salt, and pepper in the slow cooker and stir to combine.
Cover and cook on low for 4-5 hours or high for 2-3 hours, until chicken is cooked through and vegetables are tender.
Remove the chicken from the slow cooker and shred it with two forks, then return it to the pot and stir in the frozen peas.
Tear each biscuit into 4 pieces and drop them on top of the soup, making sure they're mostly submerged.
Cover and cook on high for an additional 30-45 minutes, until the dumplings are cooked through and fluffy.
Gently stir before serving to distribute the dumplings throughout the soup.