Experts are working to define the human epoch, and chickens figure prominently.
At the 35th Annual International Geological Congress in South Africa, which is happening right now in Cape Town, scientists and expert have banded together to propose the delineation of what they're calling an Anthropocene epoch—a new, modern geological period in the Earth's history wherein humans have had extensive impact on the planet. Hang on, hang on, before you get too excited about humans finally getting to take credit for something, it's not exactly good news. "The warming temperature, higher sea levels, ash from fossil fuels, plastic waste, a dramatic increase in erosion, the spread of animal species around the world and radioactive particles left around the world from nuclear bomb tests would all contribute to permanent changes in the Earth's rocks, the scientists said," according to a report in The Independent. So yeah, our impact on the planet has been pretty powerful, but not great.
As scientists and researchers try to figure out what the "Golden Spike"—"the marker that scientists can point to years hence—perhaps millions of years hence—and say, 'There! That's the start of the Anthropocene Epoch,'" explains the BBC—of the age of humans is/was, there are some markers of civilization that may provide valuable clues. Clues like: chickens and chicken fossils.
"It has become the world's most common bird," University of Leicester Professor of Geology Jan Zalasiewicz told The Guardian. "It has been fossilized in thousands of landfill sites and on street corners around the world."
After World War II, chicken consumption really took off all over the world—and, today, 60 billion are slaughtered each year. This is a vastly different practice than even as recently as the early 20th century, when meat was a luxury and chickens were mostly kept for their eggs. "The transition to the ubiquitous meat of today began with the discovery of vitamin D in the 1920s, meaning that the birds could be housed indoors all year round, rather than let out in the summer to soak up sunlight," Damian Carrington writes. What followed was factory farming and raising chickens for large-scale food production—then the introduction of antibiotics, vaccines, and subsequent drastic reduction in chicken diversity. "This makes the bird even more suitable as the type fossil of the Anthropocene," Carrington says. "The same chicken leaves bones, bigger and differently shaped to its ancestors, all over the world."