Place the chicken thighs in the bottom of the slow cooker.
Add the sliced mushrooms, carrots, potatoes, onion, and garlic on top of the chicken.
Sprinkle the dried thyme over the ingredients, add the bay leaf, and pour the chicken broth into the slow cooker.
Season with salt and black pepper, then stir gently to combine everything.
Cover and cook on low for 6 to 7 hours until the chicken is tender and the vegetables are soft.
Remove the bay leaf, then shred the chicken lightly with two forks or leave the thighs whole.
Stir in the chopped parsley just before serving.