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, then return the shredded meat to the slow cooker.
05 - Melt the butter in a small saucepan over medium heat. Whisk in the flour to form a roux and cook for 1 to 2 minutes until lightly golden.
06 - Slowly whisk the heavy cream into the roux, heating until the mixture thickens, then stir it into the slow cooker.
07 - Stir well, re-cover, and cook on LOW for an additional 20 to 30 minutes until the soup is creamy and heated through. Remove the bay leaf, taste, and adjust seasoning as needed before serving hot.