Season roasters with salt and pepper inside the chicken's cavity and on their skin. Place on a baking sheet lined with foil. Create a divider between the 2 chickens with a thick piece of aluminum foil. Rub 1 of the chickens all over with the five-spice powder and stuff with 3 garlic cloves and 2 orange quarters. Squeeze the other 2 orange quarters over the chicken and place 1 underneath a leg and 1 underneath a wing.
Stuff the other chicken with sage leaves, the remaining 3 garlic cloves, and 2 lemon quarters. Squeeze the other 2 lemon quarters over the chicken and place 1 underneath a leg and 1 underneath a wing.
Roast for 1 1/2 hours until skin is crispy and juices run clear and drumsticks pull away from the chicken easily. Let rest for at least 10 minutes before carving.