Wash the chicken and put it in about 1 1/2 litres of boiling salted water. Peel onions and add with bay leaf and peppercorns. Cook the chicken for about 1 hour. Meanwhile boil eggs hard in about 10 minutes, rinse with cold water, peel and cut into slices. Wash and clean celery, cut into small pieces and blanch in boiling salted water for about 2 minutes.
Wash and quarter apples and cut out the core. Cut the fruit flesh into small pieces and sprinkle with lemon juice. Chop the walnuts. Stir mayonnaise, yoghurt and approx. 100 ml of the chicken stock until smooth (use the rest of the chicken stock for the pumpkin soup). Season with salt and pepper. Take the chicken out and remove the skin. Remove meat from the bones and cut into bite-sized pieces. Mix all the salad ingredients and cover and leave to stand for about 30 minutes. Season to taste again.
Season with salt and pepper. Take the chicken out and remove the skin. Remove meat from the bones and cut into bite-sized pieces. Mix all the salad ingredients and cover and leave to stand for about 30 minutes. Season to taste again. Wash the lettuce leaves, place them in a bowl and serve the salad