Place the diced chicken breasts, diced potatoes, diced carrots, diced celery, diced onion, minced garlic, dried thyme, dried rosemary, and bay leaf in the crockpot.
Pour the chicken broth over the ingredients in the crockpot. Season with salt and pepper, to taste.
Stir the ingredients to combine, ensuring that the chicken and vegetables are evenly distributed.
Cover the crockpot with the lid and cook on low heat for 6-8 hours or on high heat for 3-4 hours, or until the chicken is cooked through and the vegetables are tender.
If you prefer a thicker stew, you can make a slurry by mixing the flour and water in a small bowl until smooth.
Once the stew is cooked, remove the bay leaf and discard it.
Serve the chicken and vegetable stew hot, garnished with chopped fresh parsley, if desired.