1. Bring 1 3/4 cups broth to a boil in a medium saucepan. Add orzo; cook 10 minutes or until done. Drain.
2. While orzo cooks, heat a large saucepan over medium heat. Add oil to pan; swirl to coat. Add carrot, celery, onion, and chicken; cook 3 minutes, stirring constantly. Stir in remaining 2 1/4 cups broth, 1 1/4 cups water, parsley, and thyme; bring to a boil. Reduce heat; cover and simmer 10 minutes or until vegetables are tender. Discard herb sprigs. Add orzo, spinach, juice, salt, and pepper; simmer 1 minute.