Bring the stock to a boil in a large saucepan.
Add the carrots and rutabagas and cook for 4 or 5 minutes.
Add the turnips and parsnips and cook until the vegetables are tender, about 4 or 5 minutes.
Remove all the vegetables from the stock, place in a serving dish, and keep warm.
Boil the chicken stock, uncovered, over high heat until reduced by about one third.
Remove from the heat and stir in the butter.
Add the parsley, salt, and pepper.
Pour over the warm vegetables and serve.