Chicken in a Pot with Lemon Orzo

Name: Chicken in a Pot with Lemon Orzo
Ingredients: 1 whole chicken (about 3 1/2 pounds); 3 fat garlic cloves; 2 medium carrots (about 10 ounces); 1 tablespoon olive oil; 2 lemons; 2 teaspoons dried tarragon or thyme; 5 cups sliced leeks, from 2 medium leeks, white parts only; 2 teaspoons flaky sea salt or kosher salt, or 1 teaspoon fine sea salt; 1/2 teaspoon crushed red pepper flakes (optional); 6 cups cold water; 1 1/2 cups orzo pasta; 1/3 cup finely chopped Italian parsley, plus more for serving; Freshly grated Parmesan, for serving (optional)