Spatchcocked Chicken with Cracked Olives and Herbs - Fresh-Pressed Olive Oil

Ingredients

• 2 roasting chickens, each 3 1/2 to 4 pounds
• Coarse salt (kosher or sea) and freshly ground black pepper
• 6 garlic cloves, peeled and finely grated or minced
• 2 teaspoons Aleppo pepper, or more to taste (see Note)
• 1/2 cup finely chopped fresh rosemary
• 1/2 cup olive oil, divided use
• 1 cup Castelvetrano, Cerignola, or other green olives, pitted and coarsely chopped
• 1/4 cup fresh orange juice
• 1/4 cup chopped fresh oregano
• 1/2 cup chopped fresh flat-leaf parsley, plus extra leaves for serving