01 - Add 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 butter in a small saucepan over medium heat. Whisk in the flour and cook the roux for 1 to 2 minutes, stirring constantly.
06 - Slowly whisk the heavy cream into the roux and heat until thickened. Pour this mixture into the slow cooker and stir to combine.
07 - Re-cover the slow cooker and continue cooking 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 salt and pepper as needed. Ladle hot into bowls and serve.