Wash the chicken, cut it at the back and press it apart, breaking the breast bone. Season chicken from the inside with salt and pepper. Line a baking tray with baking paper. Lay the chicken with the inside flat on top. Mix maple syrup, chilli sauce, vinegar, mustard and Worcester sauce. Brush the chicken with the marinade. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 hour.
Wash pumpkin thoroughly, grate dry, cut in half and remove seeds. Cut pumpkin into cubes. Peel, wash and dice potatoes. Wash and quarter apples, remove seeds. Cut quarter into slices. After 20 minutes cooking time, spread pumpkin, potatoes, apples and chestnuts around the chicken and finish cooking. Arrange chicken and pumpkin-chestnut vegetables on a plate, garnish with parsley