Preheat oven to 180 degrees C. Lightly grease a medium baking dish.
Bring a large pot of lightly salted water to a boil. Add spaghetti and cook for 8 to 10 minutes or until al dente. Drain and place in the prepared baking dish.
Melt butter in a medium saucepan over medium heat. Stir in flour. Mix in chicken stock and milk. Cook and stir until the mixture comes to a boil. Stir in about 1 1/3 cups Parmesan cheese and remove from heat.
Mix chicken stock mixture and turkey with spaghetti. Top with remaining cheese. Bake 1 hour in the preheated oven, until surface is lightly browned.