Robert F. Kennedy Jr., the nation’s top health official, has an unorthodox idea for tackling the bird flu bedeviling U.S. poultry farms. Let the virus rip.
Instead of culling birds when the infection is discovered, farmers “should consider maybe the possibility of letting it run through the flock so that we can identify the birds, and preserve the birds, that are immune to it,” Mr. Kennedy said recently on Fox News.
He has repeated the idea in other interviews on the channel.
Mr. Kennedy does not have jurisdiction over farms. But Brooke Rollins, the agriculture secretary, also has voiced support for the notion.
“There are some farmers that are out there that are willing to really try this on a pilot as we build the safe perimeter around them to see if there is a way forward with immunity,” Ms. Rollins told Fox News last month.
Yet veterinary scientists said letting the virus sweep through poultry flocks unchecked would be inhumane and dangerous, and have enormous economic consequences.
“That’s a really terrible idea, for any one of a number of reasons,” said Dr. Gail Hansen, a former state veterinarian for Kansas.
Since January 2022, there have been more than 1,600 outbreaks reported on farms and backyard flocks, occurring in every state. More than 166 million birds have been affected.
Every infection is another opportunity for the virus, called H5N1, to evolve into a more virulent form. Geneticists have been tracking its mutations closely; so far, the virus has not developed the ability to spread among people.
But if H5N1 were to be allowed to run through a flock of five million birds, “that’s literally five million chances for that virus to replicate or to mutate,” Dr. Hansen said.
Large numbers of infected birds are likely to transmit massive amounts of the virus, putting farm workers and other animals at great risk.
“So now you’re setting yourself up for bad things to happen,” Dr. Hansen said. “It’s a recipe for disaster.”
Emily Hilliard, the deputy press secretary at the Department of Health and Human Services, said Mr. Kennedy’s comments were aimed at protecting people “from the most dangerous version of the current bird flu, which is found in chickens.”
“Culling puts people at the highest risk of exposure, which is why Secretary Kennedy and N.I.H. want to limit culling activities,” she said, referring to the National Institutes of Health. “Culling is not the solution. Strong biosecurity is.”
In her plan to combat bird flu, Ms. Rollins recommended strengthening biosecurity on farms — preventing the virus from entering their premises, or halting its spread with stringent cleaning and use of protective gear.
But that is a longer-term solution. The U.S.D.A. is beginning those efforts in just ten states.
The virus first took root among wild birds, which transmitted it to domestic poultry and various mammal species. Now a single infected duck flying overhead may drop excrement onto a farm, where a chicken or turkey may ingest it.
Farmed poultry have weak immune systems and are under enormous environmental stress, often packed together in wire cages or poorly ventilated barns. Within a day, H5N1 can sicken as much as a third of a flock.
Infected birds can develop severe respiratory symptoms, diarrhea, tremors and twisting of their necks, and produce misshapen or fragile eggs. Many die gasping for breath. (Some birds die suddenly without showing any symptoms at all.)
The speed with which infected birds collapse has been cited as one reason that officials believe eggs to be safe for consumption. Most sick birds die before they can lay an egg, or are so visibly diseased that it is easy to filter them out.
Poultry farmers call the authorities as soon as they spot the signs of illness or death. If the tests turn up positive for bird flu, they are reimbursed for killing the rest of the flock before the virus spreads any farther.
If farmers were instead to let the virus make its way across the farm, “these infections would cause very painful deaths in nearly 100 percent of the chickens and turkeys,” said Dr. David Swayne, a poultry veterinarian who worked at the U.S.D.A. for nearly 30 years.
The result would be “inhumane, resulting in an unacceptable animal welfare crisis,” he added. (Methods to cull birds can also be cruel but at least are generally faster.)
Farmers who cull infected flocks must also clean the premises and pass audits before restocking. They are often eager to resolve the crisis quickly. Simply stepping back would have serious financial consequences.
The strategy “means longer quarantine, more downtime, more lost revenue and increased expenses,” said a U.S.D.A. scientist who was not authorized to speak to the media.
Mr. Kennedy has suggested that a subset of poultry might be naturally immune to bird flu. But chickens and turkeys lack the genes needed to resist the virus, experts said.
“The way we raise birds now, there’s not a lot of genetic variability,” Dr. Hansen said. “They’re all the same bird, basically.”
Public health regulations would forbid the very few birds that might survive an infection from being sold. In any event, those birds might only be protected against the current version of H5N1, not others that emerge as the virus continues to evolve.
“The biology and the immunology doesn’t work that way,” said Dr. Keith Poulsen, the director of the Wisconsin Veterinary Diagnostic Laboratory.
Letting the virus spread unchecked would also likely lead to trade embargoes against poultry from the United States, he added: “There’s a huge economic loss immediately.”
In one interview with Fox News, Mr. Kennedy also suggested that the virus “doesn’t appear to hurt wild birds — they have some kind of immunity.”
In fact, while ducks and shorebirds may not show symptoms, H5N1 has killed raptors, waterfowl, sand hill cranes and snow geese, among many other species.