The turkey you're about to eat weighs twice as much as it did a few decades ago

The turkey that will be at your Thanksgiving table this week probably won't look anything like it would have decades ago. 

Today's turkeys are a lot bigger — more than double the size — and faster-growing than the birds our parents or grandparents ate.

For reference, here's what the turkey President John F. Kennedy pardoned in 1963 looked like compared to the one President Barack Obama pardoned 50 years later:Modifications by Erin Brodwin/Business InsiderThat's a big bird.

Still, demand for the birds is greater than ever. Americans consumed 16 pounds of turkey per person in 2014, and turkey consumption has increased by more than 110% since 1970, according to the National Turkey Federation.

Breeding bigger birds

Up until the 1950s, farmed turkeys were pretty much the same size as wild ones.

But to meet growing demand, American turkey farmers began to breed birds both for their size and their speed of growth, Suzanne McMillan, senior director of the farm animal welfare campaign of the American Society for the Prevention of Cruelty to Animals told Mother Jones in 2014.

Since 2012, turkeys have weighed roughly 30 pounds. 

Modifications by Erin Brodwin/Business Insider

The trouble with bigger birds

That increased size has actually led to fewer turkeys getting slaughtered. According to a USDA report, 232 million turkeys were slaughtered in 2015, down from a peak of 293 million turkeys in 1996. Over time, male turkeys eventually grew so heavy that they could no longer mate with hens. For this reason — and other reasons including choosing to breed fewer males than females — most of today's turkeys are bred through artificial insemination.

Today, turkey farmers are also prevented from giving turkeys hormones, according to USDA regulations. They are allowed to use antibiotics, however, to "prevent disease and increase feed efficiency," according to a 2011 fact sheet. Unfortunately, antibiotic use in livestock is a major contributor to the rise of superbugs in humans that are resistant to our best medications. So in recent years, the FDA has begun cracking down on the drugs. Some turkey producers have started going antibiotic-free, with the exception of using the drugs to treat turkeys when they get sick. 

This Thanksgiving though, enjoy your turkey — just know that this isn't your grandma's Thanksgiving bird.

Tanya Lewis contributed to an earlier version of this post. 

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