Load the crockpot: Add chicken, carrots, celery, onion, wild rice, garlic, bay leaf, Italian seasoning, thyme, parsley, salt, pepper, and 8 cups broth into the slow cooker. Stir to combine.
Cook until tender: Cover and cook on low for 6–8 hours or high for 4 hours, until chicken is cooked through and rice is tender.
Shred the chicken: Remove chicken, shred with two forks, and return to the soup.
Make the creamy base: In a small saucepan, whisk flour with half and half and milk over medium heat until slightly thickened. Stir into the slow cooker.
Adjust consistency: Add more broth if soup is too thick. Taste and adjust seasoning as needed.
Serve: Garnish with fresh parsley or cracked pepper. Serve with crusty bread for dipping.