In a bowl, combine all of the brine ingredients.
Place each whole chicken in a large ziplock bag. Each of my chickens fit in a gallon freezer bag.
Split the brine between the two and seal shut. Place the ziplock bags on a dip baking tray to avoid any messes if the ziplock bags break. Put the tray in the refrigerator and let rest for 2 hours to a maximum of 5 hours.
After the chicken has completed its brine, remove it from the refrigerator and the ziplock bag. Pat the chickens dry and place in a tall baking dish.
Preheat the oven to 375°.
Combine the ingredients of the spice rub in a small bowl. Rub each of the chickens thoroughly, inside and out, with the spice rub.
Insert a lime and cilantro in the cavity of the chicken. Bake, breast side up, for 1 ½ – 2 hours. Remove from the oven and cover with aluminum foil. Let it rest for 10 minutes. Squeeze fresh lime juice on the chicken and carve to serve.