In a large soup pot, cover the chicken with water and add the vegetables. Simmer gently for two hours. Remove the chicken carefully and let it cool. Remove the skin and bones and pull the chicken flesh apart into bite sized pieces. Strain the stock and return it to the pot. Add the garlic and greens and cook about five minutes, adding a little water if necessary. Return the chicken to the pot and heat through. Adjust the seasonings and serve.