Separate kale leaves of a head, cut the central part of the root with leaves and stew them into boiling water for about ten minutes. Rinse leaves in cold water and cut into strips. On the water, cook finely chopped leek and celery, along with chicken cut into bigger pieces. Add kale and pepper, pour water, add salt to taste, add the vegetable seasonings and cook for about 60 minutes. When cooked add 1 tablespoon of olive oil.