With the chicken breast side down, use your poultry shears and cut along each side of the backbone. Once you've done that, turn it over and press down on the bird to flatten it out.
Combine all the chopped herbs, garlic, salt, pepper, and olive oil in a small bowl. Rub the chicken all over with the herb mixture, keeping most of it on the breast and leg/thigh meat of the bird. Let the chicken sit out on the counter while you heat up the grill.
Preheat the grill until it is very hot and clean off the grates.
Grill the chicken, breast side down for 10 minutes with the grill cover open. Carefully loosen the chicken skin from the grates if it has gotten stuck, then turn over the chicken.
Reduce the heat to low so that you can maintain a temperature of about 350F. Either shut off one of the burners and turn down the others or move the coals so that you have cooler area in the middle with more heat on the sides. Either way you want only indirect heat on the breast meat with direct, low heat on the legs.
Cover the grill and continue cooking the chicken, breast side up until done, 160F, 35-40 minutes on my grill.