Combine the broth, barley, onions, carrots, thyme, and sage in a large pot.
Bring to a boil. Reduce heat and simmer, covered, for 1 hour.
Meanwhile heat the oil in a large nonstick skillet over medium heat. Add the
garlic and sauté for 1 minute. Increase the heat to medium-high, add the
mushrooms, and season generously with salt and pepper. Stir-fry the mushrooms
until they give up their liquid and most of it has evaporated, about 5 minutes.
Set aside.
To the broth, add the mushrooms, chicken, 1 teaspoon salt, and pepper to taste.
Simmer, covered, for 20 minutes longer. Stir in the parsley. Serve immediately.