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Not Again

Will the Next Pandemic Start With Chickens?

This spring, a virulent strain of bird flu ripped through U.S. farms. The public hardly noticed. That we could ignore the disease shows just how little we’ve learned about the origin of new viruses.

In the right conditions, you cannot mistake the fact that you’re near an industrial chicken farm. There’s a walloping odor of mold and feces, even death, as if you’ve come upon a raccoon corpse rotting in a creek. Or that’s how Greg Lanc describes it.

Lanc grows corn and soybeans on a plot of land in Butler County, Nebraska, a half-mile north of a massive industrial chicken farm. Within three miles lie two other chicken facilities, built over the last few years, putting Lanc’s home in the middle of a collective metropolis of more than two million chickens. “You constantly wonder, do I smell?” Lanc told me when I visited this summer. “Like my clothes, my house—if I go somewhere, do I smell like dead chickens?” I felt lucky that the summertime heat helped dampen the stench.

Had I been here in March, Lanc said, it would have been overwhelming. He’d been worried, given that a virulent strain of avian influenza was surging through the country’s poultry farms. Indeed, late in the month, the Nebraska Department of Agriculture confirmed that the epidemic had reached Butler County. The agency did not announce which farms were infected, but it was not hard for Lanc to ascertain. He drove the county’s unpaved roads until he found a site where the commotion made it clear the birds inside were being, to use the industry euphemism, “depopulated.” Once killed, they would be rendered into compost, which would eventually be spread across local fields.

Two weeks after that announcement, Lanc came home to find the smell so strong that, even indoors, even with the windows shut, he had no appetite. So he leashed his black Lab and walked across his neighbor’s fields to investigate. The compost bins on the farm nearest his house, he noticed, were so full that the carcasses were spilling over the top. The soil near the compost bins had been recently tilled, and Lanc could see bones and feathers scattered across the surface, as if dead chickens had been mixed into the ground to make more room in the bins. There had been no public announcement that this farm was infected with avian influenza, but it was clear to Lanc that, one way or another, a lot of birds had died. When he filed an official complaint with the county health department about the odor—and the potential health risks—he was told there was nothing it could do.

In April, compost sheds at Wolfpack Farm, adjacent to Greg Lanc’s homestead in Butler County, Nebraska, were piled so high with dead chickens that the carcasses spilled over a concrete wall.

Consider this pile of chickens just one grim snippet from yet another plague year. In Wisconsin, television news reporters caught footage of crews, some clad in white hazmat suits, pushing wheelbarrows full of dead chickens onto a loading dock. Nearly three million corpses were dumped into truck after truck. In early April, three fox kits in three separate Michigan counties were found shaking and walking in circles; all three tested positive for avian influenza and died. An additional kit that also tested positive survived, but it was blinded and could not be released back into the wild. This summer, samples from dead seals tested positive for the virus. Given the 170 corpses that washed up along Maine’s beaches in June and July, more than twice the usual number, it seems likely that many more seals contracted influenza, too.

For most Americans, this devastation has amounted to little more than a blip on the evening news—the price of eggs gone up. Nearly three years into our own still-raging pandemic, perhaps it’s hard to care about chickens, even when they’re dying by the tens of millions. But that very fact—that it’s easy for us to ignore trouble in the ecology that surrounds and supports us—also shows what little we’ve learned about how pandemics begin. The expansion of U.S.-style industrial agriculture across the globe has driven the spread of viruses. It’s more than possible that the next Covid, or something far worse, could emerge on our own farms.

Every viral pandemic since the dawn of the twentieth century seems to be the result of the same phenomenon: “spillover,” in which a virus adapted to some other species finds its way into human bodies. The SARS-CoV-2 spillover has become the most famous, and genetic analysis supports the idea that this leap occurred in a live market in Wuhan, China. In reaction, the Chinese government banned the trade, sale, and consumption of most wild animals. The World Health Organization has called on other countries, too, to halt any trade of live or minimally processed wild mammals—or bushmeat, as it’s sometimes called.

These are worthwhile steps, to be sure, though we shouldn’t let ourselves presume that thereby we’ve solved the problem. Bushmeat is an easy target, at least for Americans, since it seems distant and dirty, the kind of commodity that a real civilization would have already left behind. But the global wildlife trade is responsible for a tiny fraction of disease outbreaks, pointed out Colin Carlson, a biologist at Georgetown University who studies infectious diseases and global change. As for pandemics—the rare but consequential diseases that manage to spread across international borders—“it’s this one,” Carlson told me. “It’s just this one.”

The worst pandemic in modern history rocked the world in 1918: 500 million people infected, 50 million killed. Today, in our more populous world, an equally vicious virus would kill 200 million people, more than 30 times the death toll of Covid-19 so far. The disease is remembered today as Spanish flu, though that name does not record where the pandemic began, just one country where the press was willing to admit to the scale of the problem. Virologists now believe that it emerged from birds on a farm in Kansas, then spread to a nearby military base, whose soldiers helped carry it across the world. It’s a reminder, Carlson noted, that a pandemic can start anywhere, even here in the United States. It’s also a reminder of why flu is so troubling: It can infect the domesticated animals we raise. The biomass of the world’s poultry is three times that of all the wild birds combined. Pigs, which can also carry the flu, make up even more biomass. That’s a massive stockpile of virus, no bushmeat needed.

Typically, a strain of influenza that affects chickens cannot invade human cells, nor vice versa. Thus, for many years, when poultry flocks suffered from “highly pathogenic avian influenza,” or HPAI—the broad name given to any influenza strain that results in rapid and widespread chicken death—no one much worried about the human risk. The reason is hemagglutinin, one of the two key proteins that make up the virus’s outer shell. Hemagglutinin binds with the surface of target cells in a host’s body, imitating the attack. But not all cells are the same, and the shape of the hemagglutinin determines which cells a virus can open, something like a key fitting into a lock.

The calculus changed in 1997, after an outbreak of bird flu struck Hong Kong. Eighteen people contracted the flu; six died: a stunning mortality rate. The only blessing was that the virus seemed incapable of jumping from human to human. Every case in Hong Kong appeared to involve direct contact with birds. So after every domesticated bird in the city was killed—1.5 million in total—the crisis came to an end.

That’s small comfort, really: As the succession of recent Covid variants has demonstrated, viruses are shifty. Once they invade a host, they turn its cells into maniacal Xerox machines, churning out copy after error-riddled copy of their genome. Given the rapid rate of reproduction involved, evolution can proceed at hyper-speed. The human genome has evolved just 1 percent over the past eight million years. Many RNA viruses can change that much in just a few days.

Even this process, at least, is somewhat predictable, or predictable enough that scientists can update the flu shots each season. Our immune systems crank out antibodies that match the shape of the viruses our bodies have encountered; if we can correctly guess what strain of hemagglutinin may dominate in the coming year, virologists can create matching vaccines.

The bigger worry, then, is a second trick: When two different influenza viruses invade the same cell, segments from the genome of each may be grabbed up and packaged into a single, new viral beast. This process is known as reassortment. Most of the time, the result will enfeeble the virus. Not always, though.

Say there is a particularly savage form of chicken flu that can unlock a human cell but is not passed easily among people—the kind of virus that struck Hong Kong, for instance. Put that virus inside a human body that is already infected with the seasonal flu and, voilà, by reassortment, a supervirus might emerge: highly deadly, spread easily, unknown to human immune systems. It’s the kind of scenario that keeps virologists up at night.

Though debate remains, something like this appears to have triggered the 1918 pandemic. We know more definitively that the two following influenza pandemics, in 1957 and 1968—which each killed at least a million people—resulted from avian-human viral reassortment. The outbreak in Hong Kong was the result of reassortment, too, though of a different kind: The virus that emerged there mixed up genes from various bird species, domestic and wild. Human-adapted viral genetics played no part: It was just dumb evolutionary luck that yielded a form of hemagglutinin that could unlock the human cells, the equivalent of a million monkeys pounding on keyboards and yielding Shakespeare.

The great fear in 1997 was that this savage new virus would reassort once more, and gain the superpower of easy human-to-human spread. Thankfully, that has not happened. Still, the past quarter-century has been plenty eventful when it comes to avian influenza: More than 800 people have contracted the virus, and more than half of those have died. Other strains of bird flu have proved capable of jumping to humans, too, and humans have passed the disease among themselves, though never in high numbers. But the strain of influenza first identified after the Hong Kong outbreak is still out there, morphing and changing its genetic code, spreading through more and more birds, further across the globe.

Today, more than 20 percent of migrating ducks, gulls, and shorebirds are known to carry some form of influenza. Often they are asymptomatic, even when they contract a virus that is deadly to turkeys and chickens. Good news for ducks, perhaps, but less so for the rest of us: As asymptomatic carriers, they can spread the disease far and wide as they soar across the continents, leaving virus-filled shit as mementos of their passage. In 2006, in an attempt to track the HPAI strain that first hit Hong Kong as it began to spread beyond Asia, the U.S. Department of Agriculture launched a surveillance program, which included the collection of hunter-harvested birds from each state to test for HPAI.

In late 2014, waterfowl began dying en masse along the Pacific Coast. The surveillance program revealed that HPAI had arrived on our shores. Over the next few months, HPAI spread eastward, eventually ravaging Midwestern poultry farms. No human infections were documented, but the consequences were still devastating: Once a single chicken contracts this virus, you can expect the entire flock to die, though not before they suffer symptoms like internal hemorrhaging, swollen heads, and loss of coordination. Diarrhea and nasal discharge scatter new bits of virus across the farm. Fifty million birds were killed in an effort to contain the outbreak; the U.S. government spent $879 million cleaning up the mess.

Subsequent genetic analysis suggested that the virus that spread across farms in 2015 was another reassortment: Some of its genes were drawn from the strain that killed in Hong Kong in 1997, while some came from a milder strain native to North America. This mixture allowed government messaging to have it both ways. The Centers for Disease Control and Prevention, in an apparent effort to quell any panic, declared it a homegrown virus. “North American lineage avian influenza viruses have very rarely infected people,” officials wrote, emphasizing that the deadly “Asian” strains had not been found in the United States. The USDA, however, emphasized that the 2014 virus did contain genes derived from Asia—as if only a foreign invader could explain the problems on U.S. farms.

Genetic studies suggested that the virus jumped into domestic populations only once; the subsequent spread was farm-to-farm—and driven by the industry itself. Perhaps local sparrows were infected thanks to sloppy disposal of infected chickens, then sneaked into barns. Perhaps someone walked around carelessly in feces-stained boots. Perhaps, as some farmers believed, the wind carried the disease, and it was sucked into barns via intake fans. In the precarious system of industrial farming we’ve adopted, any one of these small actions can result in the deaths of millions of birds.

A hundred years ago, chickens were nearly everywhere: More than 90 percent of U.S. farms had poultry, and sold the eggs and meat locally. As late as 1930, the average flock contained around two dozen birds, though by then farms on the Delmarva Peninsula were conducting the first experiments in growing chickens by the tens of thousands. Farmers pioneered new technologies: They combined cheap corn with vitamins and antibiotics to pump the birds up to heftier weights. They used artificial lighting to override the limits of natural growth cycles. By the 1970s, a midsize flock might contain 100,000 birds. The industry was becoming vertically integrated, too: From the feed mill to the hatchery to the processing plant, everything became absorbed into a small set of big-name companies like Tyson and Perdue Farms. Throughout the second half of the twentieth century, the number of chickens in the United States exploded—growing more than a thousandfold in just six decades—while the number of chicken farms dropped by 98 percent. Today, the local “farmers” who raise chickens are better thought of as babysitters, feeding corporate-owned grain to corporate-owned chickens, which, once they grow big enough, will be trucked to corporate-owned slaughterhouses, sliced apart, wrapped in plastic, and stamped with corporate logos.

This system depends on a strange new kind of bird, unlike any chicken in the wild, its genes shaped through years of human selection to promote astounding rates of growth. Throughout the twentieth century, the average weight of a “broiler,” as a meat chicken is known in the industry, increased by nearly two-thirds; the time it took to grow that big dropped by 60 percent. Chicken genes have become intellectual property, owned mostly by just two companies, which is why the chickens raised on modern farms sound more like Apple products than animals: the Ross 308, the Cobb 500, and so on.

This bizarre ecosystem—a barn full of genetically identical birds—is, it turns out, a hothouse for viruses. Typically, their parasitic nature imposes a limit on virility: Kill too many hosts, and you’ll have no one left to infect. A million or more birds packed together, though, means there’s no dead end: just more and more bird bodies for the virus to invade. Even without reassortment, then, these farms produce superflus. In a 2018 study, published in Frontiers in Veterinary Science, a team of researchers found that since 1959, when influenza was first identified in birds, commercial flocks in high-income countries have been the site of more than three dozen viral conversions, wherein fairly mild forms of bird flu have morphed into HPAI.

These flus, along with other diseases, have prompted the birth of a strange new phrase: “biosecurity.” Farms became the sorts of places where workers need to wear overalls and boot covers and submit to footbaths—if not full showers—when entering, where vehicles need to be disinfected at the gate. It’s a vision of the farm as a sealed world, entirely separate from nature.

This regime extends beyond chickens. Alex Blanchette, an anthropologist at Tufts University, studies the U.S. pork industry; his research has included fieldwork inside production facilities. In the midst of an outbreak of the alarmingly named porcine epidemic diarrhea virus—which swept across the country in 2013, killing 10 percent of the nation’s pigs—Blanchette noticed companies going to extraordinary lengths to maintain biosecurity. Management examined pay stubs to make sure that if various employees lived together, they all worked in the same facility. That way human contact could not provide the virus a mechanism to spread across the farm. A manager who supervised the kill floor knew he was not supposed to get beers after work with a manager overseeing the rearing facility. Blanchette told me it was only recently that he acquired the language to describe what was happening within the company: This was a form of social distancing. On a pig farm, he said, everyday life “is kind of like a casual pandemic.”

A decade after the bird flu emerged in Hong Kong, an epidemiologist named Rob Wallace co-published a paper that, by tracking the virus’s changing genome, confirmed that the virus had emerged in Guangdong, China, the province where many of Hong Kong’s chickens were raised. But Wallace was haunted by questions that genetic sequences could not answer: Why Guangdong? Why 1997? He found himself stumbling into new disciplines in which he wasn’t always entirely comfortable: sociology, geography, political economy.

It’s not wrong to think of Guangdong as a viral hot spot. Once filled with wetlands, and home to many wild birds, this strip of land in southeastern China endured “one of the greatest migration events in human history,” as Wallace puts it. Rural villagers poured into what’s become China’s most populous province. Ecosystems were tarnished and removed; backyard flocks colonized urban slums at the same time that U.S.-style production revolutionized local agriculture. Between 1985 and 2000, China’s poultry production jumped nearly tenfold.

In March, workers from the U.S. Department of Agriculture traversed a pit where millions of chicken carcasses had been dumped. The Iowa property belongs to Rembrandt Foods, one of the world’s largest egg factories.

If industrial farming is a recipe for HPAI, industrial farming amid such chaos is a recipe for global catastrophe. The mangled ecosystem doubles as a stirred-up pot of viral populations, as species—birds wild and domestic, mammals, humans—all cross paths. It’s reassortment just waiting to happen, in other words. The same 2018 Frontiers in Veterinary Science study that cataloged viral conversions in high-income countries noted that wet markets in Hong Kong and China alone have, through reassortment, produced highly pathogenic strains of influenza at least 42 times. The same process has been repeated in other countries with transitioning economies—places where “traditional” poultry farms are being replaced by modern, intensive production systems. And it’s not just bird flu. After people across the world became infected with H1N1 influenza in 2009, virologists identified the strain as a reassortment, and pinpointed pig farms in Mexico as the source. The first infections were detected in California. It’s one of the few pandemics that in the United States we do not identify by its site of geographic origin.

Other infamous viruses—like Ebola and, yes, SARS-CoV-2—arrived not on farms, but from wildlife. Wallace makes a compelling case, nevertheless, that the root cause is really the same: the global expansion of an agricultural system that was pioneered in the United States and seems to consider any form of ecological destruction justified if it leads to cheaper food and greater profit. Forests must be clear-cut, leaving less space for wild species. As the local economy gets supercharged, bushmeat hunting can grow in scale, too, so food can be supplied in mass quantities. By treating the world’s ecosystems as a resource to be mined, we’ve opened Pandora’s box, setting its once far-flung viruses on new paths of collision.

Such a view upends the typical geography of hot spots: The spillover may happen in the developing world, but the problem originates, really, in the so-called First World. Indeed, every public-health biologist I talked to hated the way these viruses are depicted as exotic problems. Jason Rohr, an ecologist focused on public health, told me that our First World appetite for more and more products means resources are stripped out of the developing world and scattered across the globe. Our First World appetite for travel has airplanes linking every distant node. “If we just got rid of the developed world and strictly had the developing world, I think there’d be way less risk of a pandemic.”

The first infected birds to reach the United States this year—or at least the first birds we know about—were an American wigeon and a blue-winged teal. Both were shot down in the marshes along the Edisto River, just southwest of Charleston, South Carolina, this January. We expected these birds, really: Europe was already in the midst its worst-ever outbreak of bird flu, and in late 2021, the disease reached Canada, too.

Within a week of those first detections, the scale of the problem became clear. Infected birds appeared hundreds of miles away, in North Carolina, then in Virginia and Maryland and Florida. By February 8, the inevitable happened: A turkey flock in Indiana suffered increased mortality. The samples sent to a laboratory confirmed that, as suspected, the problem was influenza—in particular the strain the USDA now dubs the “Eurasian H5.” (Influenza viruses are classified by the structure of their surface protein; the “H5” label indicates one of 18 known configurations of hemagglutinin.)

The disease spread rapidly, first up and down the East Coast, then westward toward the heartland. An outbreak in mid-March at a single farm in Iowa forced the slaughter of 5.3 million chickens. According to the Storm Lake Times Pilot, the birds were killed by “VSD+,” or ventilation shutdown: The air in the barns was turned off so that the temperature rose until the birds both suffocated and overheated. (The “plus” refers to the suggested addition of more heat and/or carbon dioxide, which helps asphyxiate the chickens.) Activists from an organization called Direct Action Everywhere raided the plant after the culling; a video they released showed that a few dazed chickens had somehow managed to survive the heat. Corpses and viscera lined the floor.

VSD+ is controversial for obvious reasons, though really there is no pleasant way to kill several million birds, especially when speed is of the essence. And one of the takeaways from the 2015 outbreak was the need for more speed: The USDA figured that birds had managed to shed too much virus, in feces and vomit, before they were killed. The agency set a new goal of dispatching infected flocks within 48 hours of a presumed infection, if not half that time. So VSD+ was added to the list of approved emergency depopulation methods.

Most of the chicken farms in Butler County, Nebraska, supply a cult favorite foodstuff: the $4.99 rotisserie chicken at Costco. To keep that low price—the store’s signature loss leader—Costco has begun to work outside the four-way oligopoly of big chicken companies. A company called Lincoln Premium Poultry, described by a spokesperson as “created for Costco in collaboration with Costco,” opened a plant in Fremont, Nebraska, in 2019. That same year, the first new barns were built in Butler County. Next came the trucks, delivering chicks and picking up full-grown broilers ready for slaughter—leaving slow snowstorms of white feathers in their wake. Finally, this spring, bird flu followed: Five days after the infection in Iowa, one of Butler County’s massive chicken farms tested positive, too.

As Greg Lanc drove me on a tour of the county—recounting where he saw men in hazmat suits during the outbreak, noting the creeks and lakes where he’s sampled the water and found alarming bacterial growth—the truck often shuddered over potholes. “This is typical,” he said. “Our roads just get their ass beat.” It’s one of the hidden costs of the chicken farms, which are serviced by a constant supply of trucks transporting chickens and delivering feed.

The dirt highways ran in perpendicular lines, perfectly geometric axes, over the gently rippling landscape of corn and soybeans, creeks and grassy marshes. Every few minutes, on the far horizon, a line of silver would appear: the roofs of another set of barns in the distance.

In 2019, Jonathan Leo, an environmental lawyer who helped locals fight Costco’s move into Nebraska, compiled a list of all the barns that supplied Lincoln Premium Poultry. “I saw this cluster of gigantic barns in Butler County that was unlike any other concentration of LPP barns anywhere else in the state of Nebraska,” he told me. These were huge facilities—up to 16 barns per site, with each barn home to roughly 47,500 chickens—and five were owned not by locals, but by a North Carolina–based firm called Gallus Capital. Butler County, Leo noted, has no zoning restrictions. Like China, like Africa, this piece of rural Nebraska had been rendered a site for absentee landlords to wring out profit.

Last year, the activist group Mercy for Animals released videos depicting the gruesome conditions in one of the barns that supplies LPP. Some of the birds had grown so heavy that they could no longer stand; stuck on their backs, they’d been trampled by their cousins. The video prompted a New York Times op-ed, in which the general counsel for Costco said the images depicted “normal and uneventful activity”: a glimpse, then, of what life is like inside the barns in Lanc’s backyard, where each six-pound bird gets less than one square foot of space. An LPP official told me that the company is seeking strategies to improve animal welfare, though she cited no specific changes implemented since the video’s release.

In 2021, Mercy for Animals, an advocacy organization, photographed conditions at a Costco industrial farm in Nebraska. Left: A warehouse held chickens in tight proximity. Right: A worker shoveled dead chickens into piles.

Lanc, in his late forties, favors a black baseball cap, its bill just barely curved, and sports slightly bushy sideburns. He looks less like a farmer than a skater—or race car driver, in this case, a sideline hobby for much of his life. He worked for a while, too, selling race car equipment. “I’ve worked a job my entire life,” he told me, “sometimes two jobs, just to keep being a farmer.” His 200-acre farm is less than half the size of the average farm in the county, but he considers it a family heirloom. His great-grandmother bought a portion of the homestead nearly a century ago. Now he’s looking for ways to escape the stench. One of Lanc’s neighbors, Sam Barlean, told me he’d already bought a house in the nearby town of David City. “Had to friggin’ run like hell, man,” he said.

After the positive tests in Butler County, the Nebraska Department of Agriculture followed national regulations and imposed a 6.2-mile “control area” surrounding the infected barns. Any farm within that circle would be subject to increased testing, and needed permits before moving chickens, which typically requires a flock to test negative twice, two days in a row. Nonetheless, the morning after one of the infections was announced, Lanc drove past one facility, named S&S Broilers, where chickens were being loaded into trucks. This was less than a quarter-mile downwind from a second facility, owned by Gallus, that appeared to be infected. “It was absolutely crazy,” Lanc said: It felt like a recipe for sending virus-infected chickens out into Costco stores across the country.

The Nebraska Department of Agriculture said that the S&S Broilers flock had been immediately tested and came back negative, so the birds were moved at once, without waiting for a second day’s test. After consultation with the USDA, a permit was granted allowing the chickens to be shipped to slaughter. The USDA did not respond to a request for clarification on why the permit was granted.

The owner of S&S Broilers did not respond to phoned and emailed requests for comment. In an interview, Jody Murphey, the managing partner of Gallus Capital, declined to confirm whether avian influenza hit any of his company’s barns. But he emphasized how seriously he and other producers take the illness. “It’s the last thing we want,” he said. “It’s not good for our operations. It’s not good for the industry as a whole. It’s something that we want to keep at bay.” As for the overflowing compost bins that Lanc observed, Murphey guessed that a different virus was the culprit, perhaps a kind of hepatitis that has been plaguing the industry for more than a year. The resulting mortality sometimes forces farmers to “be creative in how we cover [carcasses] and how we turn the compost piles,” he said. Jessica Kolterman, the director of administration at Lincoln Premium Poultry, acknowledged that at the time of Lanc’s complaint, a local grower “was not adhering to best management practices related to composting,” an issue LPP immediately addressed.

No one I asked, however—not Murphey, not the Nebraska Department of Agriculture, not Lincoln Premium Poultry—said they were aware of a second problem that Lanc had observed: manure being loaded onto trucks at one of the Gallus-owned barns near his house, within the control area, another act that should have required permits. (Lanc had notified the county, while Barlean had reached out to state and federal officials.) It made Lanc wonder how much more could happen at these farms beyond the notice of the people who were supposed to be in charge. The entire quarantine seemed so slipshod, really: Lanc and Barlean both told me that no agency ever reached out to signal that their homes lay near an outbreak of this flu. They saw ducks and geese swimming in pools of rainwater next to piles of rendered chicken carcasses; workers discarded two hazmat suits in the roadside ditch near Lanc’s house. Lanc said he’d asked the county sheriff to remove them, but when I visited four months after the outbreak, the suits were still there, dusty and dried out by the sun.

By the end of April, as the outbreak passed its peak, more than 37 million birds had been culled across the country. In the United States, at least, the death toll was lower than in 2015, which perhaps suggests that, despite the laxity Lanc observed, farmers have tightened their biosecurity. On the other hand, this year’s virus found new classes of victims. The 2015 outbreak hit mostly turkey and egg farms, where the birds live relatively long lives, and therefore have more time to contract a virus. This year, broilers suffered, too—as have a wide range of species. More than 50 wild avian species tested positive in North America, twice as many as in 2015. So have several mammals: the foxes and seals, along with bobcats and a coyote pup, among others. For the first time in the United States, we can add humans to the list. A prisoner in Colorado, who was euthanizing infected birds as part of a work-release program, tested positive in late April. The United Kingdom suffered its first human infection, too, a 79-year-old man who owned 125 ducks. Fortunately, both patients recovered.

How worried should we be? While this virus’s ability to infect mammals is alarming, it remains unlikely that you, reader, will come down with it, unless you make some stupid decisions: wading incautiously through piles of goose shit, say, or eating raw birds. But you can think of the biblical stories that emerged this year as a reminder that your concern is overdue. Bird flu need not be highly pathogenic to launch a human pandemic; recent studies suggest that the outbreaks in both 1957 and 1968 seem to have involved mild strains of bird flu that reassorted with human viruses. Even when birds aren’t dying in huge numbers, we need to be worried about the flu.

We live amid a cloud of virus—and not just influenza, as first SARS-CoV-2 and now monkeypox have proved. Colin Carlson recently co-published a paper that modeled how the ranges of several thousand mammal species will shift as the climate changes. These ranges are transforming already, he found: Species are crossing paths, bumping into strangers, exchanging their viruses. Carlson estimates that these new interactions could produce 15,000 spillover events in the coming decades. Each is a potential pandemic. “You cannot put the Anthropocene back in the bottle,” he says.

Chicken, meanwhile, is on pace to become the world’s most-consumed protein within the next few years. In some ways, we might consider that a good thing. International officials have developed various “pathways” that predict how the world might change, in terms of global warming and economic development. The more hopeful futures—in which warming is relatively contained and people are still able to eat enough food—involve a shift away from beef production, with a corresponding increase in chickens and pigs. A rise in chicken farming means that, even if we shutter every live bird market and somehow stop the bushmeat trade, the peril of spillover remains, and in fact is increased. “There is no way out of flu,” Carlson said. “We can close all the other doors, and it will just be us sitting alone in a room with the inevitability of flu pandemics. That is something that I think is not at all in conversations in this space right now, which freaks me out.”

Part of the answer, Carlson believes, has to be a better global public health system. Spillover is ecological, yes, but not every spillover results in an epidemic. Not every epidemic spreads to become a pandemic. “Pandemics happen because we don’t share information quickly, because we don’t have vaccines ready to go, because the world is becoming more connected,” he said.

Nonetheless, our food system is approaching a day of reckoning. When I visited in July, Nebraska had been flu-free for months—heat can kill the virus—but the disease had just begun to hit backyard flocks in Nevada and Oregon, as well as one commercial turkey farm in Utah. Across the country, from Florida to Minnesota to Oregon, samples from wild birds were still yielding positive tests. This pattern of spread suggests that HPAI is now endemic in certain wild birds. They will deliver this virus again and again, each time they wing through town. Scientists have already observed this new regime in Northern Europe.

Vaccines are an important, if complicated, part of the solution. Sloppy vaccination campaigns can actually drive viral evolution—and allow the vaccinators to carry the disease from farm to farm. For the virus to be contained, every one of the billions of chickens and turkeys and ducks raised in the United States will have to be treated, an enormously expensive operation. Vaccination can also undermine disease surveillance, because it’s difficult to distinguish between infected birds and immunized birds. “Introducing a vaccine is likely to result in trade restrictions on our poultry and poultry product markets,” a spokesperson from the USDA’s Animal and Plant Health Inspection Service indicated to me. The USDA’s research wing is hoping to develop a vaccine that could be distinguished, somehow, from the wild virus. Industry leaders are gathering in Europe in October to discuss how to open a path forward for vaccines.

Jody Murphey of Gallus Capital told me that, after two decades in the poultry industry, he’s concluded that the United States has the world’s safest system. “We have biosecurity protocols that are enforced via contracts,” he said: Vertical integration brings discipline, in other words. Better to have fewer farms, bigger and more centralized, than many small farms that are hard to police, and where birds are likely to bump into their oft-infected wild cousins. This system also delivers cheap food that can feed a growing world.

In the wake of the crisis, some veterinary experts, too, have published papers calling for the further intensification of farming. What would that look like? China offers one potential model: There, pig farms have been built inside concrete buildings that stand as high as 13 stories and house more than 10,000 animals inside. Access is so restricted that workers must wait in a holding zone for two days before heading inside the quarantined facility. Don’t worry about them: According to a report in The Guardian, the facilities include tennis courts, so the workers don’t get cabin fever. The idea, in essence, is to create a separate pigworld, completely severed from the rest of nature. To me, it sounds less like a farm than a prison, filled with inmates both porcine and human.

An equally sci-fi option might be to abandon the dirty animals entirely and instead grow their meat tissues inside of laboratories. But do we want our food to be produced in industrial labs, with feedstocks and waste streams? What if, instead of trying to further withdraw from the world around us, we decided to put ourselves in greater alignment with the ecosystem that supplies our food?

This is the solution that Rob Wallace has settled on. He now runs an organization called the Agroecology and Rural Economics Research Corps, which investigates the potential for overhauling the food system in the Upper Midwest to create a healthier and more just planet. Ideally, he thinks, our food would be produced by many people on small plots of land, amid a diversity of plants and animals, relying not on chemicals and other industrial products but on the services provided by the ecosystem itself.

The spillover problems at China’s wild-bird markets may make species diversity seem like an inherent risk. But Wallace believes that nature itself can provide ­biosecurity: The problem is less the number of species in a system and more the way they’re jammed together in unstable configurations. Though the science is still being debated, in general it appears that intact and biodiverse ecosystems provide a “dilution effect” that dampens viral spread. That’s probably because a healthy ecosystem includes some hosts that easily catch any given virus but don’t effectively spread it: lots of dead ends. Certainly, sustaining genetic diversity within a flock can provide biosecurity. Some animals will have inborn genetic resistance to a virus, which will be propagated to future generations. Wallace would like to see the reproduction of chickens returned to the farms, rather than conducted in separate (corporate-owned) hatcheries. You can’t ever stop spillovers, he told me, but if you have biodiversity on the farm, as well as in the surrounding landscape, diseases won’t spread at the scale they do now.

There are potential middle-ground approaches, too. Several companies have developed new chicken breeds, designed to grow more slowly and develop more robust immune systems. These can be penned indoors during migration seasons, but in smaller flocks, so they’re not packed beak-to-beak. Smaller, slower-growing flocks also mean a single infection won’t doom millions of birds. Matthew Wadiak, the CEO of a company called Cooks Venture, told me that by the 1980s, it should have been clear that the chicken industry was headed in the wrong direction: Breeders had over-selected for breast size, thereby compromising the birds’ health—often rendering them immobile—and as a result our own health, too.

Lanc told me that, in the 1980s, his family still raised their own chickens. His grandmother’s skillet-fried chicken remains a beloved memory, though these days he can’t stomach the bird. Other families maintain the tradition still, and, as it turned out, the Butler County Fair overlapped with my visit. On my last morning in the county, I decided to stop by, hoping to chat with a few backyard poultry farmers about how they’d fared through the outbreak. But when I arrived, the beef weigh-in was underway, so the open-air poultry barn was mostly empty: just a few young children wandering from pen to pen, admiring the menagerie.

I saw hefty white broilers and exotic pigeons, geese, and ducks, along with one turkey so perfectly formed that he appeared to have been lifted from the pages of a children’s Thanksgiving book. It was a slice of wholesome Americana, and, after my several days of contemplating the perils of modern capitalism, it should have provided a bit of cheer. Now, however, I could only see these birds as a viral breeding ground: the potential beginnings of the next mixed-up superflu. Was this barn the continuation of a timeless tradition, or one more menace? It’s too soon to know. The answer will depend on the choices we make: what kind of public health system we build, which forests we allow to be mowed down—and, in no small part, how we decide to feed ourselves.