Place chicken, salt, water and the celery leaves in a large stockpot or slow cooker. (Save the celery stalks.) Cover, bring to a boil. Reduce heat and simmer for 1 to one and a half hours or until chicken is tender.
Remove chicken and strain broth into a bowl. Chill broth in refrigerator until top is covered in fat. Skim fat.
Remove fat, skin, and bones from chicken. Discard. Cut meat into bite sized pieces. Set aside.
Return broth to pot. Add chopped celery with carrots, barley, brewer’s yeast and lemon juice. Cover and simmer 20 minutes.
Add chicken, spinach and green beans. Cook 15 more minutes until beans are tender. Cool and serve. It will keep refrigerated for one week or frozen for a month in an airtight container.