Add Ingredients to the Slow CookerPlace the chicken, wild rice, onion, carrots, celery, garlic, broth, and seasonings into the slow cooker. Cover and cook on LOW for 7-8 hours or Shred the ChickenRemove the chicken from the slow cooker, shred it with two forks, and return it to the soup. Make a Creamy RouxIn a small saucepan, melt the butter over medium heat. Stir in the flour and cook for about 1 minute. Gradually whisk in the milk, cooking until the mixture thickens. Pour it into the slow cooker along with the heavy cream, stirring well to combine. Let It Thicken & ServeAllow the soup to cook for another 15-20 minutes on LOW to let the flavors meld. Serve warm, garnished with fresh parsley, and enjoy with a side of crusty bread.