1. Put chicken in a large pot, add water and bring to a boil. Skim any foam from the surface, add barley and chicken broth. Bring to a boil. Simmer for 1 hour.
2. Chop celery, slice carrots, finely chop onion and mince garlic.
3. In a skillet, heat vegetable oil. Saute celery, onion, carrots and garlic, until onions are translucent (about 7 minutes).
4. Chop potatoes.
5. Add potatoes and sauteed vegetables to the pot. Simmer for 10 minutes, until the potatoes are tender.
6. Add kale, parsley and lemon juice. Season with salt and pepper. Cook for another 15 minutes.
7. Remove chicken, shred with a fork and return to the pot. Serve hot.