Heat the oven to 400°F. Lightly oil a 9-by-13-inch baking dish with the olive oil.
In a large bowl, combine the ground turkey, egg, breadcrumbs, Parmesan, parsley, Italian seasoning, garlic powder, salt, and black pepper. Mix gently until combined, taking care not to compact the meat.
Shape the mixture into four small oval loaves. Arrange them in the prepared baking dish, leaving space between each one.
In a separate bowl, stir together the orzo, marinara sauce, and chicken broth. Pour the mixture around the meatloaves and spread the orzo into an even layer.
Cover the dish tightly with foil and bake for 25 minutes. Remove the foil, stir the orzo around the edges of the dish, and check that it is tender and the meatloaves are cooked through. The center of each loaf should reach 165°F.
Sprinkle the mozzarella over the meatloaves and return the uncovered dish to the oven for 3 to 5 minutes, until the cheese melts. Let the dish rest for 5 minutes before serving so the orzo can absorb any extra sauce.