Preheat the oven to 450F. Cut the onion and red pepper into pieces and place at the bottom of a roasting pan.
Pat the skin of the chicken dry with paper towels and rub with oil, dried herbs, and salt and pepper.
Staff the cavity with fresh herbs, garlic, and 1/2 the lemon.
Roast the chicken for 20 minutes. Reduce the oven temperature to 350F and continue to roast until the juices run clear, about 40 minutes or up to an hour.
Let the chicken rest about 10 minutes and then carve. Serve with remaining 1/2 lemon, cut into small wedges.