Preheat the oven to 200°C, fan 180ºC, gas 6. Place the carrots, parsnips, potatoes, red onions, chopped rosemary and thyme in a large shallow roasting tray. Drizzle over half the oil and toss everything together until well coated in the oil and herbs.
Place the chicken thighs and chipolatas on top and pour over half the stock. Drizzle over the remaining oil and roast in the oven for 40-45 mins until the chicken and vegetables are golden and cooked through.
Transfer the chicken, chipolatas and vegetables to warm serving plates. Place the roasting tin on the hob and heat the pan juices left behind.
Pour in the remaining stock, scraping up any leftover bits off the bottom of the tin with a wooden spoon, and simmer until you have a lovely thin gravy.