Heat oil in a large pot over medium-high heat. Chop onion, peel and chop carrots, and mince garlic; add to pot. Cook, stirring occasionally, until onion is softened, approximately 10 minutes.
Add broth, orzo, Worcestershire sauce and herbs (except parsley), bring to a boil. Reduce heat to medium low and simmer, covered, until orzo is tender but still has some firmness, about 6 to 8 minutes.
Dice chicken and add to pot; season with freshly ground black pepper and salt. Simmer until chicken is cooked through, about 10 minutes. Remove from heat, stir in peas and parsley; heat through. Season with additional salt and pepper as needed. (Be sure to remove bay leaf before serving).
Serve with sliced oranges.