01 - Add the chicken, mushrooms, carrots, celery, onion, garlic, wild rice, thyme, rosemary, bay leaf, salt, and black pepper to the slow cooker.
02 - Pour in the chicken broth and stir everything together to distribute evenly.
03 - Cover and cook on LOW for 6 to 7 hours or on HIGH for 3 to 4 hours, until the chicken is fully cooked and the wild rice is tender.
04 - Transfer the chicken to a plate and shred using two forks. Return the shredded chicken to the slow cooker.
05 - Melt the butter in a small saucepan over medium heat. Whisk in the flour and cook for 1 to 2 minutes to form a light roux.
06 - Slowly whisk the heavy cream into the roux and heat until the mixture thickens. Pour the cream mixture into the slow cooker and stir to combine.
07 - Re-cover and cook on LOW for an additional 20 to 30 minutes until the soup is creamy and heated through.
08 - Remove and discard the bay leaf. Taste the soup and adjust seasoning as needed. Ladle into bowls and serve hot.