Q: I've heard that fish meal is part of a chicken's diet. How much of the stuff can a chicken eat before its identity is in doubt?

A: Fish meal is the bony, protein-laden byproduct remaining after the oil is extracted from menhaden. This oily fish accounts for about half of our total annual fish catch. The oils, which are very unsaturated and react quickly with air to produce a tough, plastic-like film, are used in oil-based paints.

Most poultry growers limit the weight of fish meal to 1 percent of the feed's weight. They've found that exceeding that proportion causes a fishy flavor and smell. Even more important is cost. Soy, sunflower and cottonseed press cakes, also high in protein, are less expensive than fish meal. Consequently, they comprise the bulk of chicken's diet.

Q: In your column of July 17, you discussed several ways of preparing salsify. You did not mention a stew made with it. Any suggestions on how one might prepare it? Do you know where salsify might be sold in the Washington area?

A: A mock oyster stew ought to contain milk or cream and onions, just as do most oyster stews. And it ought to be thickened with a blond roux (flour and butter cooked together, then used to thicken the milk). Here's a recipe: MOCK OYSTER STEW (2 servings)

1 pound salsify

1 quart cold water

2 teaspoons white vinegar

1 quart boiling water

1 teaspoon salt

1 medium onion

4 tablespoons butter

2 tablespoons pastry or all-purpose flour

2 cups milk or half-and-half

1 1/2 teaspoons salt or to taste

1/2 teaspoon ground white pepper

1/2 cup good dry sherry

Oyster crackers for garnish

Peel the salsify with a potato peeler. Plunge each root as peeled into cold water containing a teaspoon of white vinegar. When you've peeled all the roots, cut them into 2-inch lengths. When these are all cut, drop the lot into the quart of boiling water to which you've added the salt and the second teaspoon of vinegar. Bring back to a boil over high heat, reduce to medium-low and simmer the roots, covered, for about 10 minutes until the largest piece can be easily poked through with the tip of a paring knife. Drain through a colander.

Mince the onion and fry in butter until translucent. Add flour and cook until it turns light tan. Remove from flame and bring milk or half-and-half to a boil. Add this to the flour-butter-onion mixture and whisk together vigorously. Return to the burner on high heat and bring to a boil, whisking continually to prevent lumps. Reduce to medium-low and simmer the sauce 10 to 15 minutes. During the last five minutes, add the cooked salsify, the salt, the pepper and the sherry. Save a tablespoon of the sherry and stir it in just before serving the stew. Oyster crackers complete the illusion.

Salsify comes from one of two sources: Belgium and California. You will find the fresh roots costing anywhere between $2 and $3 per pound. There's only a small waste factor, so it's not as exorbitantly priced as it appears. There are at least four stores that carry it periodically in the Washington area:

Sutton Place Gourmet, Washington and Bethesda (both of these stores had it when I called);

Safeway International, McLean (the produce manager will gladly order it for you);

Giant Gourmet, McLean (it is stocked periodically);

Larimer's Market, Washington (it is rarely carried fresh but is always available bottled).

If you should purchase bottled or canned salsify, you will find it somewhat less flavorful than fresh. Canning, however, does not seem to affect salsify as negatively as it does peas, beans or carrots. Canned salsify needs no further cooking -- add it to the finished stew just before serving.