Mix the parsley, thyme, rosemary, garlic, shallots, black peppercorns and pink peppercorns together in a bowl. Add the olive oil to cover the herbs/spices. Set aside 2 tablespoons of the marinade.
Place the chicken thighs in a resealable plastic bag. Add the marinade and marinate overnight in the refrigerator.
Preheat the grill to medium.
Remove the chicken thighs from the marinade, pat with a paper towel and place, fleshy-side down, on the hot grill. Grill until cooked through, turning once, 7 to 8 minutes per side. Finish with the reserved 2 tablespoons of marinade and some flaky salt. Serve on top of your favorite salad.