FAYETTEVILLE, Ark. -- Modern science has re-engineered your Thanksgiving classic, but it has done so the old-fashioned way - through selective breeding rather than hormone additives. The result is a big-breasted, socially-awkward bird, says a poultry specialist at the University of Arkansas, but who wants to eat social skills?

It is a commonly-held myth that turkeys are injected with hormones to make them bigger, according to Frank Jones, an extension section leader at the Center for Excellence in Poultry Science. "In actuality, that's been illegal since the 1950s," he said. "There are still things to worry about - not the least of which are the microbes on poultry - but hormones are not a concern."

Cruising through the supermarket aisles this time of year, though, it is not uncommon to find a flock of 12 to 20-pound turkeys nestled between the meat and dairy shelves. This alone begs the question, "If not through hormones, how do turkeys get so big?"

Jones is happy to answer: "Scientists built a better bird."

In prior decades, birds were commonly administered a synthetic male hormone called diethylstilbestrol. This chemical was inserted as a capsule beneath the muscles of one wing. "Males of any species tend to have more muscle than females, and that's what you sell - that's what you eat - muscle. So birds who got this male hormone dose tended to grow more muscle per unit weight of bone," said Jones.

Diethylstilbestrol may have been good for turkeys, but it caused cancer and birth defects in humans. The Food and Drug Administration banned its use in poultry in the mid-1950s, and in 1974 the Environmental Protection Agency made any use of the hormone illegal. So scientists had to find an alternative.

What they fell back on were the same, basic techniques of animal husbandry that breeders have practiced for thousands of years - using the birds' own genes to grow bigger turkeys. The process is not high-tech, said Jones: "It's not really a matter of gene-splicing. We use selective breeding - picking the characteristics that are most appealing to the consumer and consistently mating the birds who show them."

But this age-old process created an unusual predicament, requiring a modern-day solution. "Domestic turkeys are all artificially inseminated," Jones said. "The reason is that they've been bred with such big breast muscles that the male cannot mount the hen. If these turkeys were let loose in the wild, they would die out for lack of reproduction. They just can't do it on their own."

The hunger for breast meat has placed turkey reproduction entirely in human hands, but there are some aspects that even science can't duplicate: the role of a mother, for instance.

"The mother turkey never has any contact with her offspring," said Jones. "In the wild, chicks imprint on the mother and learn survival skills from her. If a turkey goes into a turkey house and imprints on its hatchmate, it doesn't get the right kind of social or survival information. Because of that, turkeys come across as being pretty stupid.

"Basically what we've done is bred a big-breasted, socially-awkward bird," Jones said. "But they make a pretty good meal."

Unfortunately, good genes can only take a turkey so far. Another way to help a bird reach its maximum growth is by ensuring that it stays healthy. Breakthroughs in nutrition and disease control have enabled more turkeys to live longer, grow stronger and ultimately to yield more meat.

For example, corn and soybean diets give turkeys the proper nutrients to build massive muscles. Also, vaccines against respiratory and intestinal infections can save the lives of countless birds while passing along no harmful effects to human consumers.

"The majority of vaccines have no effect on humans whatsoever," said Jones, "But there is a period of two weeks before the turkey is killed when the bird stops receiving this medication. That time allows the medicine to work out of the bird's system."

Modern science may have made domestic turkeys sexually frustrated and socially graceless, but it has also made them safe and nutritious. We can all be thankful for that.

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