THURMONT, MD. -- One man's leftovers are another man's livelihood. While home cooks have gratefully transformed the last of their holiday food into soups or stews, Ross Smith is busy smoking turkey tails, grinding cajun turkey sausage, chopping turkey mincemeat, selling turkey pot pies, processing turkey bologna, salami and pastrami, and cooking up new products for the thousands of birds left in his freezer. Even during the intervening 10 months until the next turkey season, Maryland's largest turkey farmer will be turning turkey parts into profit.

Smith has cashed in on a trend that has skyrocketed in recent years. Consumption of turkey parts jumped from 701 million pounds in 1981 to more than 1 billion pounds in 1986. Convenience, smaller family units, smaller ovens, cost and nutrition are all part of the phenomenon of turkey as a year-round bird.

Before the trend took hold, Smith was working in New York City as manager of one of the stores in the now-defunct variety chain, W.T. Grant Co. Trading in his oxford cloth for flannel, he resigned to run Hillside Farms, his parents' turkey operation in this northern Maryland town, "flooring" his about-to-retire father, according to Smith.

Nevertheless, Smith always had it in the back of his mind that he would someday run Hillside Farms, which originally started as a hobby project of his mother's. But the five turkeys Pauline Smith kept in the yard grew to 50 after the second year, and by the time there were 5,000 turkeys, the senior Ross Smith decided to drop the family's feed store business and help make his wife's extensive hobby into a full-time profession.

When Ross Smith, Jr., took over the business about 10 years ago, the company was primarily involved in whole turkeys. Smith gathered tips from small turkey processors in other states, attended poultry trade shows and gradually diversified the operation. Every year Smith adds a few new products, and now half of Hillside Farms' annual production of 75,000 birds is used for further processing (a tiny operation compared to turkey giants like Swift and Louis Rich, which each process millions of birds every year).

The Smiths' turkey farm is now deserted, as all the birds were slaughtered before the holidays. In April, freshly hatched turkeys, weighing about 3 ounces each, will be brought to the farm. Fast converters of grain to meat, they will grow to 30 pounds in about 19 weeks. The toms, which have a better yield, will be used for further processing. The parts must be cut by hand, as the birds' bones are too big for machine processing, according to Smith.

Five miles from the farm is Smith's processing and retail operation, a small white building packed with activity and friendly chatter. Travelers from the Washington metropolitan area who have heard about the place drop by on country drives, and there is a steady clientele of locals who regularly frequent the shop. In fact, one gets the feeling that everyone in Thurmont knows the Smiths, if not through turkey, then through family or work.

Calvin Burrier, who works at the local feed store coop, has known the Smiths for 30 years and buys turkey parts every week from Hillside. He also happens to supply the feed (corn and soybeans) for Hillside's turkeys. Wearing his Master Mix-Thurmont Coop cap, Burrier buys fresh turkey breasts and bologna this day and kibbutzes with Doris Danner, who has been running the counter for the past 10 years and also happens to have a daughter who married Burrier's nephew.

A blackboard in the small shop lists the items available, a testament to Hillside Farms' diversification. Every imaginable part of the bird is divided, subdivided, smoked or processed: fresh turkey gizzards, livers, necks, roasts or steaks; turkey bacon, franks, sausage or ham; smoked turkey necks, tails, drums, wings or thighs; small turkey pies and big turkey pies. There are smoked chickens and fresh chickens and three different kinds of Hillside barbecue sauce if you want to baste your own bird.

Like other family-owned operations that don't have the time or facilities for think-tank formulations, Hillside often gets its recipes by way of family or friends. The Cajun barbecue sauce comes from a Cajun woman, now living in Thurmont, whose husband went to school with Ross Smith. The Cajun turkey sausage, a new product this year, was derived from the seasonings in the sauce. Recipes for the old-fashioned and tangy sauces come from Ross Smith (he used to work part time at a barbecue joint while going to college in North Carolina). And the turkey pot pie is Pauline Smith's recipe (with artificial yellow coloring, added to overcome the grayness of the sauce).

Behind the counter is the cramped processing area, which houses, among other equipment, Smith's smoker. On this particular morning, Smith is smoking 100 pounds of turkey thighs for turkey bacon. Marinated in a sugar cure, the thighs will be cooked for about eight hours. Smith prefers slow cooking at low temperatures which he says helps retain more flavor in the meat.

The smoker, a chrome contraption that looks like a giant refrigerator, essentially works like a convection oven, Smith says, opening its door to a puff of hot smoky air. Heat is blown in evenly throughout the oven so that there are no cold spots. Next to the smoker is a funnel filled with hickory sawdust, which slowly burns into ashes, while its smoke is channeled through a pipe into the smoker. Smith never uses liquid smoke, which he says does not penetrate well enough into the meat and does not produce a good enough exterior color.

The thighs, used to make turkey bacon, are used to make most of the other processed turkey meats as well, Smith explains. The difference between the bacon or salami and pastrami is the type of seasonings used, the time and temperature at which they are smoked and the sizes and shapes they are sliced or ground.

Smith's projects for the new year include turkey pepperoni, turkey scrapple and, following a major poultry trend, cooked turkey parts. He has already run a scaled-down version of the pepperoni recipe and is experimenting with the scrapple. He tried putting turkey livers in it, but found the flavor to be too strong. (He sells most of Hillside's turkey livers to a game park in Pennsylvania, where they are fed to the animals.)

So with all the turkey products at his disposal, what does Smith choose for his own lunch? "I like a good old roast turkey sandwich," he says with a big belly laugh.

Aside from the retail operation, Hillside Farms sells its products to restaurants in Thurmont, two stands in Baltimore's Lexington Market, one stand in Baltimore's Northeast Market and one in the Cross Street Market and to about 60 small independent markets in Maryland (Chevy Chase Market, Grosvenor House of Fine Foods, Western Supermarket, Brookville market, Gaithersburg Center Market, Prime Choice Butcher Shop are among those in the Washington metropolitan area). Not all products are available at all stores.

Hillside Farms' retail store is located on Elm Street in Thurmont and is open Thursdays, Fridays and Saturdays from 10 a.m. to 3 p.m. Due to a heavy processing schedule, the store will close on Jan. 16 and reopen at the end of February. During that time, Hillside products will be sold at other retail stores, however. For further information, Hillside's phone number is (301) 271-2728.

Here are a few recipes from Hillside Farms and one adapted from the National Turkey Federation that take advantage of the turkey parts available at most local supermarkets. TURKEY NUGGETS WITH PINEAPPLE-MUSTARD SAUCE (4 to 6 servings)

1 1/2 pounds skinned and boned turkey breast

1 egg, beaten

1/3 cup water

1/3 cup flour

2 teaspoons sesame seed

Salt and pepper to taste

Oil for frying

FOR THE SAUCE:

1/2 cup pineapple preserves (substitute apricot)

2 tablespoons dijon mustard

2 tablespoons horseradish

Cut breast into 1-inch square nuggets. Mix egg and water. Add flour, sesame seeds and salt and pepper to make batter. Pour oil into a heavy saucepan or deep fryer, filling no more than 1/3 full. Dip nuggets into batter; drain off excess batter. Carefully add nuggets, a few at a time. Fry about 3 to 5 minutes or until golden brown and fork can be inserted with ease. Drain on paper towels.

To make the sauce, heat preserves, mustard and horseradish together in a small saucepan over low heat until warm. Serve as a dipping sauce for nuggets.

TURKEY PARTS WITH POACHED ORANGES (4 to 6 servings)

3 turkey thighs

3 turkey drumsticks

1 teaspoon basil

1/4 teaspoon freshly ground black pepper

1/2 cup soy sauce

1/2 cup ketchup

1/4 cup honey

1/4 cup corn oil

2 cloves garlic, crushed

FOR THE ORANGES:

3/4 cup water

1 1/2 cups sugar

3 tablespoons slivered orange peel

3 cups fresh orange sections

2 tablespoons orange liqueur (optional)

Rice or noodles for serving

Sprinkle turkey with basil and pepper. Mix together soy sauce, ketchup, honey, corn oil and garlic. Place turkey, skin side up, in a shallow baking pan and pour over sauce. Bake in a 350-degree oven for 1 hour, basting frequently.

To make poached oranges, mix together water, sugar and orange peel. Cook until slightly thickened. Add orange sections and cook about 3 minutes. Add liqueur and stir until combined. Mix basting sauce into mixture and stir. Serve over turkey and rice or noodles.

TURKEY AND SWISS ON BAGUETTES WITH MUSHROOM-WINE SAUCE (4 servings)

4 turkey cutlets

Salt and pepper

1 egg, slightly beaten

1 to 2 tablespoons milk

Dry bread crumbs

2 tablespoons olive oil

4 slices swiss cheese

2 baguettes, sliced horizontally

1 tablespoon butter or margarine

1/2 pound mushrooms, sliced

2/3 cup white wine

Salt and pepper to taste

Sprinkle cutlets with salt and pepper. Dip each in egg and milk mixture and roll in dry bread crumbs. Heat oil in a skillet over medium heat until hot. Add turkey and brown, about 3 minutes on each side.

Place a cheese slice on top of each baguette half and place on a baking sheet. Heat in a 200-degree oven while preparing mushrooms.

Remove turkey from skillet and melt butter or margarine; add mushrooms and cook over low heat about 3 minutes. Push mushrooms aside; add wine and stir to loosen up browned bits. Return turkey to skillet and simmer until sauce is slightly thickened. Make sure cheese is melted before placing turkey on top of each bread slice. Spoon mushrooms and sauce over turkey.

ORIENTAL TURKEY IN PUFF PASTRY (8 servings, 3 appetizers apiece)

1/2 pound ground turkey

1/4 pound bean sprouts

1/2 cup chopped water chestnuts

1/4 cup scallions, chopped

2 tablespoons soy sauce

2 teaspoons sherry

1 teaspoon ground ginger or 1 tablespoon grated fresh ginger

1 egg

1 1/2 teaspoons milk

2 sheets frozen puff pastry, slightly thawed

2 tablespoons sesame seeds

1/2 cup Chinese hot mustard

1 cup sweet and sour sauce

Combine turkey, sprouts, water chestnuts, scallions, soy sauce, sherry and ginger. Mix well. Cover and refrigerate several hours or overnight, allowing flavors to blend.

Beat together eggs and milk. On one sheet of pastry, evenly distribute 24 scoops of chilled mixture. Cover with another sheet of pastry. Press together edges of pastry with fork. Using a ravioli cutter, pizza cutter or sharp knife, cut pastry into 2 1/2-inch squares. Press to seal edges. Place squares on baking sheet. Brush lightly with egg mixture. Sprinkle with sesame seeds.

Bake at 425 degrees just until edges are golden, about 10 to 13 minutes. Serve immediately with hot mustard and sweet and sour dipping sauces.