Preheat oven to 375°.
Rinse chicken with cold water; pat dry. Trim excess fat. Loosen skin from thigh and leg by inserting fingers, gently pushing between skin and meat. Combine basil and next 5 ingredients (basil through pepper). Rub herb mixture under loosened skin. Place chicken on a broiler pan. Insert meat thermometer into meaty part of thigh, making sure not to touch bone.
Remove white papery skin from garlic heads (do not peel or separate the cloves). Wrap each head separately in foil; place on broiler pan with chicken. Bake at 375° for 45 minutes. Increase oven temperature to 450° (do not remove chicken from oven). Bake 30 minutes or until thermometer registers 180°. Cover chicken loosely with foil; let stand 10 minutes. Discard skin.