Preheat oven to 180°C.
Peel the beetroot, sweet potato and butternut and cut into cubes of about 1.5cm.
Peel onions and cut in half. Wash and dry the potatoes.
Add all vegetables, 1 tbsp oil and 1 tsp from each of the four herbs and spices to a large bowl and mix well using a large spoon or a tossing motion. Make sure to coat all the veg in oil and to evenly distribute the seasoning.
Empty the contents of the bowl into a large, high-sided baking/casserole dish.
Place the chicken piecesd into the same bowl, followed by 1 tbsp oil and the remaining half a teaspoon of four herbs and spices. Toss the chicken until evenly coated in oil and seasoning.
Place the chicken on top of the veg and cook in the preheated oven for 45 minutes.
Break the feta into cubes roughly the same size as the pieces of veg and set aside while you clean up.
After 45 minutes, turn up the oven temperature to 200°C and place the feta on top of the veg, spacing evenly. Leave it in the oven for at least 10 more minutes to allow the feta to become soft, longer if you prefer the veg to be slightly browner and have a bit more of a crunch.
Remove from the oven and place the chicken onto serving plates.
Mix the vegetables in the dish to coat in the cooking juices and serve.