1 to 2 days before serving this chicken rinse and pat completely dry. Gently slide your fingers between the breast and the skin to loosen the skin and make two pockets.
Repeat with the chicken thighs. Push a sprig of thyme into each of the four pockets. Season generously with salt and pepper all over.
Place in a roasting pan tented loosely with plastic wrap and refrigerate for 1 to 2 days.
When ready to roast, remove the chicken from the refrigerator and let stand for 30 minutes. Pat the chicken completely dry. Preheat the oven to 475ºF (250ºC).
Place the chicken breast-side up in a roasting dish or large oven-proof skillet. Slide the pats of butter under the skin.
Stuff the cavity of the chicken with the mix of remaining herbs. Use kitchen twine to tie the legs together.
Roast the chicken for 45 minutes then baste the chicken with the pan juices and roast for another 10, until the chicken skin is crisp and the chicken is cooked through (the internal temperature should be 155ºF (68.3ºC).
Remove from oven and let sit for 10 minutes before carving.