Start by preparing the vegetables. Chop the onion, slice the carrots and celery, and dice the potatoes.
In the slow cooker, add the chicken breasts or thighs at the bottom.
Layer the chopped onion, garlic, carrots, celery, and potatoes over the chicken.
Pour in the chicken broth, ensuring that the chicken and vegetables are fully submerged.
Add dried thyme, dried rosemary, bay leaf, salt, and pepper to taste.
Cover the slow cooker with the lid and set it on low for 6 hours.
After 6 hours, add the frozen peas to the stew and stir gently. Leave it on low for an additional 15 minutes to warm the peas through.
Once finished, remove the bay leaf and shred the chicken using two forks or leave it whole, depending on your preference.
Serve the stew hot, either in bowls or over rice for a more filling meal.