Cut Chicken in 8 parts. In a large saucepan add 2l cold water and put it on medium heat. Add chicken pieces. Add two peeled carrots, half leek, 1/4 celeriac, 1 peeled onion all cut in big chunks. Add all herbs and keep aside little thyme for service. Let it boil and then reduce the heat. Skim from time to time to avoid stock become cloudy. Cook until chicken is completely cooked. Remove cooked chicken pieces and let them cool down. Strain the stock and pour it in a clean saucepan over medium heat. Peel and dice the rest of the vegetables and add them to the chicken stock. Let it cook until all the vegetables are soft but not overcooked. Debone cooked chicken and cut it in big chunks. Add them to the vegetables and season with salt and pepper. In a small pan pour 100ml water, a spoon of vinegar, salt, and sugar. Let it boil and reduce it in half. Add the reduction to the soup. Serve with freshly baked bread.