Ingredients

5 pounds whole roasting chicken
3/4 cup salt, preferably without additives, such as canning or Kosher (optional)
1 lemon
1 lime
tablespoons butter.

Directions

* If brining the chicken, mix salt with 3 quarts water in a non-reactive pan, bowl, or pail just large enough to hold the bird snugly. Chicken should be completely covered with brine solution. Make more, if necessary. If the chicken floats, cover with a weighted plate (use canned food, etc. as a weight) to keep it submerged. Refrigerate brining container or place in a cooler with ice, for 4-6 hours.
* Remove chicken from brine, rinse and pat dry.
* Remove zest (just the colored part, not the bitter white pith underneath) from lemon and lime with a zester, peeler or sharp knife. Chop finely and mix well with the butter.
* Loosen chicken skin from meat by carefully working your hand between skin and meat everywhere you can. Push lumps of zest-butter under the skin, then spread them around by massaging skin from the outside. If the chicken wasn't brined, liberally salt the cavity.
* Squeeze juice from lemon and lime; put squeezed rinds in the cavity and set juice aside.
* If you prefer to truss the chicken, use strong string to pull drumstick ends towards each other, but not tightly--leave space so inner sides of leg and thigh can brown.
* Prepare grill for indirect medium heat, according to manufacturer's directions.
* Put chicken on grill in area away from direct heat, breast side up. Cover grill. Cook for about 2 hours, basting occasionally with lemon-lime juice. Chicken is done when leg joints move easily, or when an instant-read thermometer reads 180°.
* Remove from heat and let rest a few minutes before carving.