In the four centuries since 1621, when the leaders of Plymouth Colony gathered to feast and express gratitude, the few facts we have about the “first Thanksgiving” have been amplified and colored by folklore. And though original Pilgrim documents describe scenes from the autumn of 1621 that included killing “as much fowl as…served the company almost a week” and a “great store of wild turkeys, of which they took many” we have little direct description of that day’s menu, and some scholars believe that turkey might not have even been featured on the table.

So why is Thanksgiving so consistently and commonly tied to the turkey? We debate about pumpkin vs. sweet potato pie, about whether cranberry sauce should be fresh or shaped like a can, about whether pro football and Black Friday are sacrosanct or sacrilege—but our main-course consistency has us giving thanks by killing over 40 million sentient birds every year. Why? Why not gratitude and mercy instead?

The simplest answers: convention, tradition—and (the most American example of these) good marketing.

More than a century after the first Thanksgiving, George Washington sent a proclamation to leaders of the states, saying that November 26, 1789 would “be devoted by the People of these States to the service of that great and glorious Being who is the beneficent Author of all the good that was, that is, or that will be.” Washington’s proclamation made no mention of turkey, and evidence of its direct association with the holiday during this period is hard to find.

Only in the mid-1800s, in the years before and during the Civil war, did the idea of Thanksgiving as America’s founding harvest festival begin to take shape, largely driven by the efforts of one woman: Sarah Josepha Hale. A writer and editor of prominent “ladies’ magazines” of the day (and original author of “Mary Had a Little Lamb”), Hale used her editorial voice, penning essays and sending letters to government leaders for nearly 40 years to promote the idea of a unifying national holiday of thanks. In September 1863, President Lincoln signed a proclamation declaring Thanksgiving a national holiday.

Unfortunately for the turkeys of North America, Sarah Hale’s editorial voice also promoted and standardized the domestic holiday vision she had laid out in her most successful novel, Northwood: “The roasted turkey took precedence on this occasion being placed at the head of the table; and well did it become its lordly station, sending forth the rich odour of is savoury stuffing.” In a nation seeking to heal itself (or at least divert itself) from the horrors of the War, her vision gained traction.

In the second half of the 19th century and into the 20th, the sight of a “turkey drover” prodding his flock from farm to slaughterhouse across country roads in the weeks prior to Thanksgiving became common. But as the nation industrialized and its population expanded, food production and processing moved increasingly from backyards to commercial farms. In 1940 the National Turkey Federation (NTF) was formed and was soon marketing its “product” on a national stage by presenting President Harry Truman a live turkey in advance of Thanksgiving in 1947.

Today the NTF proudly boasts that American turkey consumption has nearly doubled in the past 50 years, with as many as 240 million turkeys killed in the United States each year. The holiday’s dependence on turkey slaughter has been normalized and reiterated, from the Macy’s Thanksgiving Day Parade Turkey Balloon to the annual “presidential pardon” to cartoon turkeys wearing pilgrim hats on wall calendars.

Our conventional yearly mechanized slaughter of 46 million intelligent birds for Thanksgiving alone gives no thanks for an abundant harvest. It is not, as Washington intended, a tradition devoted “to the service of that great and glorious Being who is the beneficent Author of all the good.” Nor does it, as Lincoln hoped, “commend to His tender care all those who have become widows, orphans, mourners, or sufferers in the lamentable civil strife in which we are unavoidably engaged.”

Our assembly-line turkey harvest does generate about $4 billion in annual revenue—nearly 6 billion pounds of turkey were sold in the US last year, roughly 75% of it by the nation’s 5 largest producers, as corporate turkey farms grow in size and family farms shrink in number.

Luckily, all conventional behaviors hold the seeds from which new traditions can grow. For over 30 years, Farm Sanctuary’s Adopt a Turkey Project has given people the opportunity to forego eating a turkey in favor of sponsoring one for Thanksgiving. For a one-time donation, you can help us to highlight the unique personalities of turkeys and showcase the cruelties from which we’re helping them to escape.

Help us to center gratitude on the Thanksgiving table, appreciating the bounty of the planet and our own capacity for compassion. Visit adoptaturkey.org to learn more.