Preheat oven to 400°F. Remove chickens from the fridge. Let sit at room temperature for 30 minutes before roasting. Brush oil over each chickens.
In bowl combine rub ingredients. Sprinkle a tablespoon of the rub mixture into the cavity of each chicken. Coat chickens with the rub and work it into the skin.
Tie the chicken legs together and secure the wings to the body.
Place the chickens on a rack in a roasting pan and roast until a meat thermometer inserted into the chicken breast reads 180°F (82°C) (about 90 minutes). If skin is browning too quickly, cover the chickens loosely with foil.
Optional: Roast 4-5 garlic heads, tops removed, with chickens. Add the roasted garlic to mashed potatoes or use it in any recipe calling for garlic (soups, stir fry, dips, stews etc). Leftover roasted garlic can be frozen.
Remove pan from oven. Transfer the chickens to a cutting board. Cover them loosely with the foil.