In a large pot combine the potatoes with salted water to cover and bring to a boil over high heat. Parboil the potatoes until half cooked, about 20 minutes. Drain the potatoes, let cool until they can be handled, and cut into large cubes. Transfer the potatoes to a large disposable foil pan, drizzle with 2 tablespoons of the oil, and toss to coat evenly. Roughly pick and tear the parsley, thyme, and rosemary sprigs, stems and all, over the potatoes, scattering them evenly. The herbs do not need to be chopped, just torn. Sprinkle the potatoes evenly with a generous pinch of salt.
Rub the chicken all over with the remaining 2 tablespoons oil, then sprinkle evenly with 2 generous pinches of salt. Put the chicken on a poultry roaster or premium grilling rack.
Prepare the grill for indirect cooking over medium heat (350° to 450°F).
Prepare the grill for cooking over medium heat (400°F).
Insert the probe. For an accurate reading, ensure that the probe tip is inserted into the thickest part of the breast (not touching the bone).
Brush the cook grates clean. If using a charcoal grill, remove the cooking grate and place the pan of potatoes on the charcoal grate between the piles of coals. Replace the cooking grate. Place the chicken on the roaster on the cooking grate, over indirect heat. If using a gas grill, put the pan of potatoes on the cooking grates over indirect heat. Position the grilling rack with the chicken in the pan containing the potatoes. Close the lid and grill the chicken over indirect medium heat until an instant-read thermometer inserted into the thickest part of the chicken breast registers 165°F, about 1 ¼ hours.
Brush the cook grates clean. Put the pan of potatoes on the cooking grates. Position the poultry roaster or rack with the chicken in the pan containing the potatoes. Close the lid and grill the chicken over medium heat until the meat probe inserted into the thickest part of the chicken breast registers 165°F, about 1 ¼ hours.
Remove the chicken from the grill, and rest at room temperature, indoors, for 10 minutes before lifting it from the poultry roaster or rack and carving. Carefully remove the pan of potatoes from the grill, transfer to a serving bowl, and keep warm until serving.
