Combine the chicken pieces and lemon juice in a bowl just large enough to hold them comfortably. Cover and marinate in the refrigerator overnight, turning occasionally.
Drain the chicken thoroughly and pat dry. Fill a plastic bag with the flour, salt, paprika, and black pepper, and shake well to mix. Put 2 pieces of chicken into the bag at a time and shake, coating completely. Shake off any excess flour.
Preheat the oven to 350°F.
Heat the corn oil in a frying pan or cast-iron Dutch oven over medium heat until hot. Fry the chicken pieces, a few at a time, until well browned and crisp. This will take about 10 minutes per batch.
Arrange the browned chicken in a single layer in a large shallow baking pan. Sprinkle evenly with the lemon zest and brown sugar. Mix the chicken stock and lemon extract together and pour around the chicken pieces. Set a thin lemon slice on top of each piece of chicken.