Clean the chicken thighs and place them in the bottom of a large pot, then pour cold water over them. Bring the water to a boil and remove the foam that forms on the surface using a spoon or strainer.
Once no more foam appears, reduce the heat to low, add the salt and the whole peppercorns.
Simmer gently over low heat for 1-2 hours. Halfway through cooking, add the cleaned and roughly chopped vegetables.
When the soup is ready, let it rest for about 30 minutes. Then remove the vegetables and the meat from the broth.
Cut the cooked meat and vegetables into smaller pieces, place them into soup bowls, and pour the hot broth over them.