Layer vegetables: Place diced onion, minced garlic, sliced celery, and sliced carrots in the bottom of the slow cooker.
Add chicken: Place chicken on top of the vegetables. Season with garlic powder, onion powder, smoked paprika, salt, and pepper.
Add mushrooms and rice: Add sliced cremini mushrooms and rinsed wild rice blend over the chicken.
Add liquid: Pour both cans of cream of mushroom soup into the slow cooker. Add chicken broth, water, fresh thyme, and bay leaves. Stir gently to combine.
Cook: Cover and cook on LOW for 6 to 7 hours until rice is tender and chicken shreds easily.
Shred chicken: Remove chicken and shred with two forks. Remove and discard bay leaves. Return shredded chicken to the slow cooker.
Add cream: Switch to LOW. Add heavy cream and butter. Stir until butter melts and cream is fully incorporated. Do not add cream on HIGH.
Season and serve: Taste and adjust seasoning. Stir in fresh parsley. Ladle into bowls and serve with crusty bread.
