Chicken in Salt Crust

Name: Chicken in Salt Crust
Ingredients: Olive oil, for brushing baking sheet; 2 (3 1/2 pound) chickens; 6 garlic cloves, crushed; 4 (3-inch) sprigs fresh rosemary; 4 (3-inch) sprigs fresh thyme; 1/2 teaspoon coarsely cracked black peppercorns; 2 tablespoons Dijon mustard; 2 tablespoons chopped fresh thyme; 2 tablespoon chopped fresh tarragon; 2 tablespoons chopped fresh parsley; Salt Crust Dough (about 1/2 recipe