Combine the salad dressing with the juice of 1 lemon and pour the mixture into the bag with the chicken.
Seal and refrigerate for 30 minutes, or up to 8 hours.
Combine the rosemary, thyme, sage, shallot, garlic, ½ teaspoon salt, pepper and olive oil in a small bowl.
Let sit while the chicken is marinating (at least 30 minutes, or up to 8 hours).
Preheat the grill to low, about 325ºF.
Remove the chicken from the marinade, discard the marinade, and pat the chicken dry with paper towels.
Insert the remaining whole lemon into the cavity of the chicken.
Rub the herb oil mixture generously over the top of the chicken.
Place the chicken on the grill, close the lid, and cook for 45 minutes over low heat or until the juices run clear when the thigh is poked with a knife.
Let the chicken sit for 5 minutes, remove the lemon from the cavity, and serve.