Slow Cooker Chicken Noodle Soup

8 cups        chicken broth 1                small onion, chopped 2                stalks celery, sliced 2                carrots, sliced 3 cups        cooked chicken, either shredded or cut 1                16-ounce package frozen egg noodles Place all ingredients except noodles into slow cooker and cook on low for 6-8 hours.  About 30 minutes before you are ready to serve soup, add frozen noodles.  Cook for 30 minutes after adding the noodles and serve.