Slice sausage into sections (about ¼ inch thick slices). Remove tails from shrimp if they are still on. Chop chicken into 1-inch pieces. Add sausage, chicken, bell peppers, onion, jalapeños, chicken broth, tomatoes, minced garlic, cajun seasoning, and salt and pepper to greased slow cooker and stir to combine. Cover and cook for 3-4 hours on low. Stir in rice and cook another 3 hours. About 20 minutes before serving, uncover slow cooker, stir in shrimp, re-cover and cook for another 15-20 minutes. Stir contents of slow cooker, sprinkle with chopped cilantro or parsley if desired, and serve hot.