A not quite "vegetarian" spin to matzo ball soup with a light Asian touch

Ingredients

For Stock:
2 3-pound chickens
2 medium carrots, cut into large chunks
1 onion, quartered
2 stalks celery, chopped
2 bay leaves
5 springs thyme
2 tomatoes, quartered
8 quarts water
5 sticks lemongrass, smashed
1-inch piece of ginger

For Soup:
1 large carrot
1 yellow squash
1 zucchini
a few springs of parsley, minced