Clean the vegetables from the bunch (carrot, leek, celery, parsley root). Dice the carrot, celery, and parsley root. Cut the leek into fine rings. Chop the parsley. Peel the potatoes and onion.
Heat the clarified butter in a large saucepan over medium heat. Add the diced vegetables, leek rings, and chopped parsley and sauté for about 2 minutes. Place the whole chicken in the pot and add the peeled potatoes and onion. Pour water over until the chicken is completely covered.
Bring to a boil over medium-high heat. Using a slotted spoon, skim off any protein deposits from the surface. Reduce heat to low, place the lid at an angle (slightly ajar), and simmer for approximately 2 hours until the chicken reaches an internal temperature of 74°C (165°F).
Remove the chicken from the pot and let cool until safe to handle. Remove and discard the skin and bones. Chop the meat into bite-sized pieces and return to the pot.
Season the pot to taste with marjoram, salt, and pepper.