Heat a large frying pan and add 2 tablespoons of the oil. Add garlic and onion and saute until tender. Take it off the stove.
Season the chicken with salt and pepper to taste. Heat the frying pan again and add the remaining tablespoon of oil. Brown the chicken on both sides and put aside.
Place the rinsed barley and 3 cups of chicken stock in a 6-8 quart pot. Bring to a boil, cover and simmer 30 minutes or until liquid is absorbed. Add remaining 3 cups of chicken stock, the browned chicken, onion and parsley. Bring to a simmer and cook, covered, over low heat until liquid is absorbed and chicken is tender.