Preheat your oven to 400°F (200°C). This will ensure a crispy skin and juicy meat.
In a bowl, whisk together the orange marmalade, olive oil, Worcestershire sauce, fresh orange juice, fresh lemon juice, dried thyme, dried oregano, salt, and black pepper.
Place the chicken halves in a large dish, skin-side up. Pour the marinade over the chicken, making sure to coat it evenly. Let it marinate for at least 30 minutes, or up to 2 hours in the refrigerator.
In the bottom of your roasting pan, scatter the thinly sliced shallots, orange slices, and lemon slices.
Place the marinated chicken halves on top of the citrus and shallot bed in the roasting pan. Roast for approximately 1 hour and 15 minutes, or until the internal temperature reaches 165°F (75°C). Baste the chicken with the pan juices every 20 minutes.
Once cooked, remove the chicken from the oven and cover it loosely with aluminum foil. Let it rest for about 10 minutes before carving and serving.
