Put the potatoes, mushrooms, shallot and garlic in a large bowl. Toss in 4 sprigs of rosemary and 4 sprigs of thyme., 1 tsp. salt, a few grindings of pepper, 2 Tbs, olive oil and 3 Tbs. balsamic vinegar. Stir everything together until well coated. Arrange vegetables on baking sheet.
Put chicken pieces in bowl and add remaining 3 Tbs. of oil and 2 Tbs. balsamic, 1/2 tsp. salt, a good amount of fresh ground pepper and toss together to coat well. Tuck chicken in to the vegetables and place remaining herbs under chicken.