Preheat oven to 375 degrees F. Lightly coat a large baking sheet with cooking spray; set aside. In a large bowl combine turkey or chicken, spinach, mozzarella cheese, 1/4 cup tomato sauce, Italian seasoning, and garlic. On a lightly floured surface roll out the pizza dough to a 15x10-inch rectangle. Cut rectangle in half lengthwise and then in thirds crosswise to make six 5-inch squares.
Place about 1/3 cup of the turkey mixture onto half of each square, spreading to within about 1/2 inch of edge. Moisten edges of dough with water and fold over, forming a triangle or rectangle. Pinch or press with a fork to seal edges. Prick tops of calzones with a fork; brush with milk. Place on prepared baking sheet.
If desired, sprinkle tops of calzones with grated Parmesan or Romano cheese. Bake 20 minutes or until golden brown. If desired, serve with warmed tomato or pizza sauce sprinkled with grated cheese.