Stir the chopped rosemary and thyme into the olive oil and set aside. Rub the pheasant inside and out with salt and pepper. Place into a close-fitting roasting pan. Pour the herb oil over top.
Bake the pheasant in the preheated oven for 1 hour, then cover with aluminum foil, and continue baking an additional hour, or until an instant-read thermometer inserted into the thickest part of the thigh, near the bone reads 180 degrees F (82 degrees C). Remove from the oven, cover with a doubled sheet of aluminum foil, and allow to rest in a warm area for 10 minutes before slicing. Baste the pheasant with the hot oil and juices from the pan every 30 minutes while cooking.