Paul Freid will soon take delivery of about 40 turkey chicks at his small farm near Lake City, where hogs and chickens already roam.

Freid is “a little nervous” about bird flu, but believes his outdoor birds’ more natural diet and healthier immune systems will shield them some from the threat.

“I trust that the way we raise our animals leads to greater health,” he said. “Might I have a problem? Sure, but any producer would say that.”

So far, nearly all of the 88 farms decimated by the highly lethal H5N2 virus in Minnesota have been confined turkey operations, meaning the birds are raised completely in barns. But whether Freid’s and other free range flocks will be at similar risk of bird flu will be tested in the coming weeks as they release the chicks outdoors for the first time this year.

Whatever happens in terms of disease is likely to reignite a debate on whether raising poultry indoors is helping or hurting the birds, as the industry tries to find ways to strengthen biosecurity ­measures to keep the outbreaks under control.

Freid and his wife, Sara, have raised free-range turkeys for the past seven years at their southeastern Minnesota farm. They do not feed the birds antibiotics, and allow them to dine on fresh grass, bugs and other vegetation, supplemented with vitamins and minerals.

Turkeys and chickens were once commonly raised outdoors, but most chickens consumed in the United States were being raised indoors by the 1950s and confined flocks of egg-laying chickens, turkeys and other livestock have also come to dominate U.S. production, with barns that house tens of thousands of animals.

Veterinary experts say there’s no evidence that free-range turkeys or chickens are any less susceptible to infection from the highly contagious bird flu virus than birds that are raised in barns.

“Because this is a new virus and it’s foreign to the United States, I don’t think any bird would have immunity if they were exposed to it,” said Jane Christopher-Hennings, veterinarian and director of the Animal Disease Research and Diagnostic Laboratory at South Dakota State University.

If anything, Christopher-Hennings said, birds raised outside might have greater exposure and risk, because the virus is known to be carried and likely spread by wild waterfowl, especially ducks.

While highly contagious and deadly to domestic poultry, animal health officials say the bird flu is not a food hazard, and is a very low risk for human health. They expect the rate of spread to keep slowing because the virus does not survive in warmer weather, but say it could return in the fall.

Beth Thompson, assistant director of the Minnesota Board of Animal Health, said that regarding bird health, diet and immune systems, “there’s probably good research out there saying that it’s better to have the turkeys in the barn, and there’s probably just as good research out there saying that it’s better that they’re outside.”

Thompson said researchers are increasingly interested in studying different ways to raise animals, but she tends to think that birds are safer indoors when other factors are considered.

“Certainly when you bring birds into a barn they’re away from predators, they’re away from parasites, and workers watch them every day,” she said. “Free-range turkeys, of course, do have more exposure to some of these diseases that run through an area.”

Thompson made the comments in an interview recently after announcing that the board canceled poultry exhibitions at the State Fair, county fairs and other events through 2015 to lessen the chances of further spreading the virus.

Free-range advantages

Freid said he has had very little loss from diseases in past years, and attributes that mostly to his free-range turkeys’ superior health.

Confined turkeys may be safer, he said, but there’s a price to pay in terms of their quality of life, the tastiness of their meat and the pollution from barns that contain hundreds of thousands of birds.

“Who still believes that it’s best for the animals to put them all into a windowless building and have them cramped together?” he said. “It might make sense economically for some people, but it kind of stops there.”

John Peterson, farmer and general manager of Ferndale Market in Cannon Falls, wrote in a recent company newsletter that “continued worry about bird flu hangs over all we do.”

Peterson raises 160,000 turkeys in a calendar year, and sells them to natural foods stores, co-ops, Kowalski’s and a few other stores in the Upper Midwest. The large majority are free-range birds that live and grow outdoors all summer, he said.

Ferndale Market’s flocks have been spared and are now feeding in the fields, he said in an interview, but the mystery of how the virus spreads has not been solved.

“For anybody who has poultry, whether it’s six ducks in the back yard or a huge poultry operation,” he said, “how could you not be worried about it, when there’s something of this kind of devastation going around?”

Steve Olson, executive director of trade groups for Minnesota’s turkey growers and egg farmers, said he doesn’t know how many commercial growers raise free-range turkeys in the state, but it’s “not a huge number.”

Olson said the industry is not likely to move away from raising turkeys and chickens in large barns, but producers hope that research now underway will explain why the ­latest flu strain spread so rapidly in Minnesota and other Midwestern states this spring.

Scientific experts believe the virus originated with wild waterfowl that carry the disease but do not get sick from it. Once here, the flu may have been blown on dust or other fine particles to infect nearby farms, at least in a few cases.

However the virus moves, Olson said the goal is to identify ways to better protect birds before next fall’s migration.

“Maybe it’s using fans in barns in more of a tunnel ventilation than the current system,” he said, or adding filters to prevent virus particles from entering barns.

Checking the dust

Hongwei Xin, professor and director of the Egg Industry Center at Iowa State University, said he and a team of researchers will soon begin sampling some of the areas afflicted with bird flu in Iowa to see if the virus attaches to small particles of dirt or dust.

“Certainly if indeed this [virus] is carried by fine dust, then something should be done,” Xin said. “Of course that’s not a silver bullet, but filtering the inlet air [for barns] would be one of the things that could be effective.”

Many Midwest turkey growers use a hybrid ventilation system, he said, which allows them to drop curtains on the sides of barns when weather is pleasant and allow natural air flow. But to filter that air would require a much more expensive mechanical system, he said.

Most egg-laying operations already have mechanical systems, Xin said. Installing filters to capture fine dust would force the fans to work harder, Xin said, and may slow down air flow and cause heat stress for the birds.

Installing new systems with fine filters, stronger fans and tighter buildings could cost up to a few hundred thousand dollars per barn, he said. “It can get pricey in a hurry.”