Bring water and barley to boil in heavy medium saucepan. Reduce heat, cover and simmer until barley is tender, stirring occasionally, about 45 minutes. Drain. Transfer to large bowl. Set aside.
Preheat broiler. Season chicken with pepper and dried Italian herb blend. Broil chicken until cooked through, about 3 minutes per side. Transfer chicken to plate; cool. Shred chicken into pieces.
Combine carrots, celery, leeks and onion in heavy large nonstick skillet. Cover and cook over low heat until tender, stirring frequently and adding small amount of water if vegetables begin to stick, about 25 minutes.
Add barley, chicken, parsley, stock and half of Parmesan cheese; stir until heated through. Season with pepper. Divide barley mixture among plates. Sprinkle with remaining cheese and serve.