Spray 3 quart slow cooker with nonstick cooking spray. Rinse rice and drain well. Combine in crockpot together with green onion, salt, chicken broth and water and mix well. Cover crockpot and cook on high for 3-4 hours.
Add mushrooms and thyme and stir gently. Cover and cook on low for 30-60 minutes longer, until wild rice pops and is tender.