How to Make It
In a pot, combine the water with the salt and sugar and cook over moderate heat, stirring, until the salt and sugar dissolve. Let the brine cool to room temperature.
Set three large oven-roasting bags in a large roasting pan. Put a chicken in each bag and pour one-third of the brine in each. Tie the bags and refrigerate for 4 hours.
Set up a grill for indirect grilling: Light 5 pounds of the charcoal on one side of the grill and hang a grilling or oven thermometer on the opposite side of the grill.
Remove the chickens from the brine and pat dry. In a bowl, combine the smashed garlic, scallions, fennel, jalapeño and ancho. Toss with 2 tablespoons of the Wild Game Rub and stuff into the chicken cavities. Tie the legs together with string. Rub the outside of the chickens with the minced garlic and 1/2 cup of the Wild Game Rub.
Set the chickens breast side down on the grill opposite the coals. Cover and cook at 325° to 350° for 1 hour. Add the remaining 5 pounds of charcoal to the grill as needed to maintain the temperature. Turn the chickens, cover and cook until an instant-read thermometer inserted in the inner thighs registers 160°, about 1 hour and 30 minutes longer. Transfer the chickens to a carving board and let rest for 10 minutes. Carve the chickens and serve.