Marinate the chickens with the marjoram, chilli, za'atar, garlic and a little oil for 2 hours or more, covered, in the refrigerator.
Roast in a hot oven for 45mins-1 hour, turning once or twice and basting with pan juices.
Fry the red onion (include a crushed clove of garlic if you like) in a little hot oil until soft, then stir in rice to 'toast'.
Slowly add stock, stirring as it cooks. When the rice is almost tender, add the coriander leaves and chopped cooked spinach. Add salt and pepper to taste.
Serve the chickens and rice with vegetables if you wish.