Heat the shortening in a large, cast iron skillet over medium-high heat. In a brown paper lunch bag, combine the flour, salt, and pepper. Shake two chicken pieces in the bag to coat, and place them in the skillet. Repeat until all of the chicken is coated and in the skillet. Fry the chicken over medium-high heat until all of the pieces have been browned on both sides. Turn the heat to medium-low, cover, and cook for 25 minutes.