Preheat the oven to 350°F. Line a large baking sheet with aluminum foil. In a large bowl, combine the ground chicken, panko, onion, parsley, garlic, lemon zest, eggs, Pecorino Romano cheese, 1 teaspoon of the kosher salt, and pepper. Lightly mix together, using your hands or a large spoon. Transfer to the lined baking sheet and shape into a loaf approximately 2 inches high and 4 inches wide, making the loaf as uniform in size as possible. Smooth the top and place on the middle oven rack. Set a timer for 30 minutes.