Family-farm advocates in rural Wisconsin are pushing back on Concentrated Animal Feeding Operations, or CAFOs, as the livestock industry becomes more concentrated. They have met with resistance from local officials.

Hundreds of residents of Pierce County, nestled along the Wisconsin - Minnesota border, are concerned about a proposed expansion of CAFOs in the county.

Danny Akenson, field organizer with a group called Grass Roots Organizing Western Wisconsin - or GROWW - asked county officials to put a moratorium on CAFO expansion.

"That moratorium did not pass," said Akenson. "In its place, the county decided to create a groundwater advisory committee which will be studying the effects that CAFOs can have on our groundwater."

Similar efforts at halting CAFO expansion have failed in other Midwest and Plains states, where advisory groups have also been formed, and where CAFOs have the potential to pollute groundwater.

Large, corporate-owned farms say their operations are more efficient than small family farms, and are simply meeting a growing demand.

Akenson said advocates are trying to work with local officials to at least slow CAFO expansion.

Known for dairy farms and cheese curds, residents of Pierce County towns - such as River Falls, Spring Valley and Ellsworth - want to preserve the rural, pristine way of life the area is known for.

"A lot of people come here looking for that rural way of life," said Akenson, "that you would not get in a place like the Twin Cities, for example."

CAFOs have been cited for a host of environmental problems as they expand across the country.

By Seth Millstein for Sentient.
Broadcast version by Mark Richardson for Oklahoma News Service reporting for the Sentient-Public News Service Collaboration

On May 11, Secretary of Agriculture Brooke Rollins announced that the U.S. is suspending all livestock imports from Mexico due to a resurgence of New World screwworm. Mexican authorities detected the parasitic fly, which was ostensibly eradicated decades ago, in southern Mexico earlier in the month after an outbreak in Panama years ago. Now, officials are increasingly concerned that the screwworm could reach the U.S., and wreak havoc on American farm animals.

Rollins says that the suspension will apply to live cattle, bison and horses, and will be renewed "on a month-by-month basis, until a significant window of containment is achieved." In the meantime, U.S. officials and cattle farmers are on edge.

"It is very, very bad, and it's not just cattle," Dr. Rod Hall, the state veterinarian for Oklahoma, tells Sentient. "The screwworms can affect any warm-blooded animal, so it would be devastating to any of our livestock species."

What is a New World Screwworm?

The New World screwworm isn't a worm at all, but a parasitic fly whose larvae infest and burrow into the tissue of warm-blooded animals. Female screwworms are attracted to open wounds, and bodily orifices in general, and that's often where they lay their eggs. Once the larvae hatch, they burrow into the host creatures' tissue with their powerful mouth hooks.

While several fly species are attracted to open wounds, screwworms are unique in that they infest healthy, living tissue, as opposed to the flesh of dead creatures. What's more, screwworms can lay up to 400 eggs at once, so even a single pregnant fly is bad news for any warm-blooded creature unfortunate enough to encounter one.

"When they get to a certain point, they fall out, burrow into the ground for a week or so, and then they turn into more flies," Hall explains. "So oftentimes, by the time a human realizes that an animal is infected, the damage has already been done, and the next generation [of screwworms] is in the soil, waiting to turn into adult flies so they can lay more eggs."

Myiasis is the official term for a screwworm infestation of living tissue, and it can kill the host creature in one to two weeks if not treated. Thankfully, myiasis is survivable if treated with larvicides, insecticides and daily cleaning of the wounds - that is, if it's detected in time, which is often the biggest challenge for livestock farmers.

Screwworm is a health threat to animals and an economic threat to meat industry producers. But it's generally not considered a public health risk to humans.

Public health officials have said that any livestock infected by the screwworm wouldn't make its way into the domestic meat supply, due to federal meat inspection laws. And although the parasite can infect humans, anybody with such an infection "would notice something" was wrong in time to treat it, Todd Thrift, associate professor of animal sciences at the University of Florida, tells Sentient.

"Unless it was someone that was just totally unaware, this is not something that rapidly affects people," Thrift says. "The probability of it being a human health threat is very, very, very, very low."

As its name implies, the New World screwworm only exists in the Western hemisphere; there's also an Old World screwworm, which is found in parts of Africa, Asia, the Middle East and Oceania. Both types of screwworms live in tropical and subtropical climates, and can't survive extreme heat or cold.

New World screwworms are endemic in South America, Cuba, Haiti and the Dominican Republic, but usually aren't found north of Panama. There are no screwworms in the U.S. - but there used to be, and it's taken quite a bit of effort to keep them out.

Screwworms Were Once A Major Issue On U.S. Farms

Until the 1960s, the New World screwworm was common across Mexico and the southern United States. After its initial detection off the coast of Guiana in 1858, the parasite became a major problem in North America around the turn of the century as America's livestock industry became more developed and expansive.

By 1920, the screwworm was a serious enough issue on U.S. farms that the Department of Agriculture produced an informational video on how to stop them. But the species was still poorly understood at this point, and it wasn't until the 1930s that a series of discoveries about the screwworm equipped scientists to begin developing a plan for eradicating them.

The key was sterilization. Female screwworms only mate once in their lives, so scientists developed a way of sterilizing male screwworms without otherwise harming them, then released the sterile males en masse into screwworm populations. This became known as the Sterile Insect Technique, and it worked: By 1966, New World screwworm was fully eradicated in the U.S., and remaining populations in Mexico were successfully eliminated by 1991.

Ensuring that the U.S. remains screwworm-free, however, has been an ongoing and international effort. Because an adult screwworm can travel up to 125 miles before laying eggs, eradicating the species in the U.S. effectively requires that Mexico be free of the fly as well. The U.S. and Panama maintain a buffer zone of sterilized flies in eastern Panama to prevent the screwworm from migrating northward, and several other international collaborations have helped keep the species' populations in check - for the most part.

How Did This Recent Outbreak Occur?

Although the U.S.-Panamanian buffer zone has largely been a success, it's not completely impermeable. There have been isolated outbreaks of the screwworm in the U.S. at various points since 1966, most recently in the Florida Keys in 2016, but all were eventually contained.

In 2023, however, a major screwworm outbreak occurred in Panama; though it's not entirely clear how the screwworm managed to escape the buffer zone, conservationists have suggested that illegal cattle trafficking is to blame. Since then, the fly has been detected in several countries north of the buffer zone, including Costa Rica, Nicaragua, Honduras, Guatemala, Belize and El Salvador.

"Panama was pretty much focusing all the sterile male flies in the Panama region to control it there," Hall says. "So once it got out of the control area without people knowing it, it had the opportunity to begin spreading. And it's hard to get ahead of it, because the animals can't talk to us and tell us they have a problem."

This is a big reason screwworm is so hard to combat: the lag time between infection and detection. It's why screwworms are a much bigger problem on cattle farms, where cows are often dispersed over a large area and aren't seen for days at a time, than on pig farms, where animals tend to be confined in tight quarters, and farmers can typically put eyes on each animal every day.

"It might be a few weeks before the authorities [in Central America] would realize that they had a case of it," Hall says. "And by then, the screwworm flies had multiplied and moved even further. So instead of being able to get ahead of it, we're kind of chasing it."

In 2024, a New World screwworm infected a cow in southern Mexico near the border of Guatemala. In response, the USDA suspended livestock imports to the U.S. from Mexico in November 2024, and increased its deployments of sterile screwworm males south of the border. By February 2025, the U.S. and Mexico had agreed to a series of enhanced security protocols aimed at preventing screwworm from crossing the U.S.-Mexican border, and the suspension was lifted.

In May, however, the USDA announced that screwworms had been detected in Mexican farms around 700 miles from the U.S. border. It was this discovery that compelled Rollins to suspend Mexican livestock imports again.

Screwworm Policy: Public Health, or Politics?

In her announcement, Rollins stressed that the import suspension "is not about politics or punishment of Mexico, [but] about food and animal safety." Nevertheless, there has been a bit of political tension between the U.S. and Mexico as of late that's worth noting.

Some of this tension has been strictly rhetorical; Mexican President Claudia Scheinbaum didn't take kindly to President Trump's suggestion that the Gulf of Mexico be renamed the "Gulf of America," for instance. But some has been more substantive, stemming from Trump's new tariffs on Mexico and his visa suspensions of certain Mexican officials.

In April, Rollins accused the Mexican government of delaying U.S. efforts to contain screwworms in Panama, and demanded that it "eliminate restrictions on USDA aircraft and waive customs duties on eradication equipment."

The two countries quickly struck a deal to resolve this issue, but the new import suspension has frustrated Mexican authorities, with Scheinbaum calling it "unfair" and defending her government's efforts to fight the parasite.

Zooming Out: Screwworms Are Common In South America

The presence of screwworms is panic-inducing for many American farmers. But in many parts of South America, they're just the cost of doing business.

"In South America, they live with this," Thrift says. "It's there all the time, and so it doesn't wipe out their cattle populations or the wildlife populations or anything else. It's just part of the normal flora."

This begs the question of how these countries deal with the screwworm. The answer is decidedly low-tech, according to Thrift: They just check the cattle for infections more frequently.

"Beef production in some of the South American countries is different because their labor is considerably cheaper," says Thrift. "Having 20 cowboys out there checking for this pest, and doctoring any animals that might have it, would not be near the labor burden that it would be in this country."

For his part, Thrift isn't quite as apocalyptic as some others about the prospect of screwworms returning to the U.S. He notes that the detections in Mexico are "still 700 miles from the [U.S.] border," and that although the parasite would cause problems for cattle ranchers, the screwworm itself "is not an unsolvable problem."

"There's definitely concern," he says, "but this is not something that is insurmountable."


Seth Millstein wrote this article for Sentient.


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Groups advocating for clean, safe water are pushing back on proposals to revive a pesticide labeling law introduced last year in Congress which would give chemical companies legal immunity from claims if their products cause cancer.

A similar measure failed in Iowa this year, despite intense lobbying by the pesticide manufacturer, Bayer.

Jennifer Breon, Iowa organizer for the group Food and Water Watch, said public sentiment has been decidedly against giving chemical manufacturers immunity from lawsuits if their products are shown to cause cancer.

"I was not surprised there was overwhelming opposition to this bill," Breon observed. "There was polling by one of the organizations in our coalition that said 89% of the people they polled on this bill were opposed to that. Hundreds of Iowans took thousand of actions to stop this bill."

The pesticide glyphosate, contained in the herbicide Roundup, is as the heart of what's known as the "Cancer Gag Act." While there is circumstantial evidence, the Environmental Protection Agency has not declared glyphosate carcinogenic Congress has not yet introduced a bill.

Bayer has four lobbyists working in Iowa. Despite the special interest pressure to pass the Cancer Gag Act, Breon noted the people of Iowa spoke up on social media, used phone banks and contacted their lawmakers, asking them to oppose it.

"This Cancer Gag Act was a cruel bill," Breon contended. "Nobody wants this in their community. To have their right to make their case in court that their cancer could have been caused by pesticide exposure."

Cancer Registry data show Iowa ranks second in the nation for cancer cases and is the only state where cancer rates are on the rise.


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By Grey Moran for Sentient.
Broadcast version by Trimmel Gomes for Mississippi News Connection reporting for the Sentient-Public News Service Collaboration

As avian flu decimated poultry flocks, two major U.S. egg producers - Vital Farms and Cal-Maine - have seen their profits and stock values soar. Between February 2024 and February 2025, Vital Farms saw its share value spike by 157.4 percent, while Cal-Maine observed an 87.4 percent uptick. These climbing stocks coincided with sky-high egg prices, often attributed to the shrinking egg supply, leaving consumers pinched.

The financial strain faced by consumers stands in sharp contrast to the financial windfalls of major egg companies - and their investors - over the course of the avian flu outbreak in the U.S. that began in early 2022. This stark disparity is emblematic of the often inverse relationship between consumer and corporate financial pressures during economic crises.

"When eggs are short, everybody wants in," Russell Diez-Canseco, the CEO of the egg producer Vital Farms, said on a call with investors in 2023, following a quarter of record-breaking revenue, as average egg prices soared across the U.S.

Vital Farms' top institutional investors - BlackRock, Wellington Management Company, Vanguard Group, Amazon, and Pictet Asset Management, according to Nasdaq - have also benefited from the company's soaring stocks over the course of avian flu. Amazon, which owns Whole Foods, may have also benefited from higher retail prices of eggs, as well as the record-level volume of sales reported last quarter.

"[Amazon] is making money in both directions. They're making money if Vital Farms is charging Whole Foods a higher wholesale price, and Vital Farms' profit margins are improving, which they are, year-after-year," Andrew deCoriolis, the executive director of Farm Forward, an advocacy research group, tells Sentient. Amazon has around a four percent equity stake in Vital Farms, which currently sells at Whole Foods for around $11 for a carton of organic eggs.

Vital Farms attributes some of its major boom in profits to avian flu. "We grew 55 percent in the first quarter of 2023, due in part to the category disruptions from avian influenza," Diez-Canseco said in another investor call. This momentum continued through 2024, as Vital Farms reported a 28.5 percent increase in net revenue over the course of the year. And as the company experienced reported outbreaks of avian flu in 2022, 2023 and 2024, it continued to rake in soaring profits to the benefit of its investors.

As profits soared, some investors bought more stock. For instance, in February of 2023, BlackRock, the world's largest asset manager, disclosed that it increased its ownership in Vital Farms to 8.3 percent of the company's stock.

Top Companies Enjoy Rapid Growth Despite Avian Flu & Record Egg Prices

Cal-Maine, the largest egg producer in the U.S., has observed a similar trajectory of record profits and rapid growth even as avian flu wiped out entire flocks. The company reported two outbreaks on its farms during 2023 and 2024, yet this was not enough to make a serious dent in Cal-Maine's egg supply: The company sold more eggs in both 2023 and 2024 than previous years, cementing its corner of the conventional egg market.

Meanwhile, during the first three months of 2025, the egg producer saw its net profits rise to $508 million, more than three times the level from a year before, and eight times more than at the start of the avian flu outbreak in 2022. As a recent report by Food & Water Watch observed, "The bird flu outbreak and Cal-Maine's price increases likely helped push its stock value up, which more than doubled since the start of the outbreak." The report also found that the company's board chair's stock value grew by over $9 million in three years.

Cal-Maine's top institutional investors include BlackRock, Vanguard, Dimensional Fund Advisors, Renaissance Technologies and State Street Corp, according to Nasdaq - some of the largest asset managers in the world that appear to be benefiting from the high egg prices. Earlier this year, the four daughters of Cal Maine's founder decided to cash in the high stock, converting $4.8 million shares of stock at $92.75 per share.

Corporate Accountability Remains Scarce

While the spike in egg prices is often blamed on supply and demand, the dramatic surge of profit has raised questions about whether Cal-Maine has raised prices beyond what is reasonable to compensate for a more constrained egg supply. This has prompted the Department of Justice to open an investigation into Cal-Maine for price gouging.

"The total number of hens and the total number of eggs produced fell maybe five percent over that first year [2022], but prices went...up about two and a half times," says Amanda Starbuck, the research director of Food and Water Watch. "[This] suggests that a lot of it has to do with corporate consolidation more than actual shortages." While there is not a 1:1 relationship between egg supply and prices, the shrinkage of the egg supply didn't appear to justify such a sharp rise in prices, according to Starbuck.

Though Vital Farms and Cal-Maine are both large, publicly-traded companies, they have different business models and customer bases.

Vital Farms, which sells pasture-raised eggs, has always priced eggs at a higher cost than conventional eggs. During the early covid pandemic, the company prided itself on not raising its price of eggs. "Despite fluctuations in demand, the cost of our eggs - nor other Vital Farms products - have not increased," stated the company on its website in 2020.

But this shifted in 2022, when Diez-Canseco announced that the company would "reluctantly and in small amounts" raise prices. Just last week, the company announced again that it would raise wholesale egg prices by at least 10 percent in response to the Trump Administration's tariffs. It remains to be seen whether Vital Farms' retailers, like Whole Foods and Target, will respond to this hike by also raising retail prices even more.

Diez-Canseco did not respond to a request for comment, but he has previously attributed Vital Farms' recent success to an increase in total eggs sold, not increases in the price of eggs - particularly as the price of commodity eggs has risen much more sharply than pasture-raised eggs over the course of the avian flu outbreak.

Cal-Maine also didn't respond to a request for comment, but the company has previously "strongly" denied the allegations of price gouging.

The Bottom Line

Flush with profits, both Vital Farms and Cal-Maine have expanded their operations over the course of the avian flu outbreak, cornering an even larger share of the egg market. Vital Farms is expected to soon begin construction on a new egg packaging and washing facility in southern Indiana, enabling the company to add165 farmers to their supply chain. Meanwhile, Cal-Maine acquired the former egg production facilities of ISE America, Inc. in 2024, adding the capacity for 4.7 million laying hens. Last month, it acquired the popular breakfast foods brand Echo Lake Foods.

"That's part of this broader trend toward just enormously large companies," says Lisa Graves, a democracy researcher and the founder of True North Research, an investigative research watchdog group, who has observed similar consolidation across the agriculture industry and other sectors. And even as these companies see record profits, she notes that worker wages remain about the same.

Referring to the sky-high egg prices and profits, Graves observed that, "it seems like consumers are being gouged in order to enrich the shareholders in ways that are really affecting the daily lives and the budgets of families across the country."


Grey Moran wrote this article for Sentient.


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