Slow Cooker Jambalaya

Name: Slow Cooker Jambalaya
Ingredients: 1 white onion , diced; 3 ribs celery, diced; 1 green bell pepper , diced; 3 cloves garlic, diced; 1 pound smoked sausage, sliced about 1/4 inch; 1 pound boneless chicken breasts and/or thighs, cut into bite-sized pieces; 1 ( 28 - ounce ) can diced tomatoes; 1 tablespoon dried oregano; 2 bay leaves; 1 to 2 tablespoons Creole seasoning (I like Tony Chachere’s Creole Seasoning); 1 pound large shrimp , shell on, thawed; 1 cup long grain white rice; 1/2 teaspoon salt, or to taste; 1/2 teaspoon black pepper, or to taste; Fresh parsley, chopped , for garnish