The Mississippi flyway is a major thoroughfare for more than 300 species of migratory birds that pass over the Midwest traveling from breeding grounds in Canada to warm winter climates south of the border. During their migtaion, they pass over a huge number of birds that rarely, if ever, see the light of day. Yet somehow, the avian flu that these wild birds can carry without even falling sick has repeatedly wormed its way into the laying hen and turkey confinements in states like Iowa and Minnesota, sickening millions of birds—the majority of which have either died or been euthanized.

This outbreak of “highly pathogenic avian influenza,” as the Centers for Disease Control and Prevention calls it, doesn’t pose a risk to humans, but it is a huge concern for the agriculture industry, and the U.S. Department of Agriculture is currently looking into a vaccine solution. Meanwhile, in the United Kingdom, researchers at the University of Cambridge are looking to chicken genes for a solution: A story published Wednesday on National Geographic’s The Plate blog tells of a genetically modified Isa Brown chicken that, thanks to a extra bit of RNA, would not be able to pass along a flu infection to the rest of the flock. As Tamar Haspel writes, “Had all the chickens in this country been so modified, the flu virus that hit poultry operations in 15 states would never have made it past Chicken Zero, the first bird infected.”

That’s an impressive advance over the current state of affairs. But as some egg producers will tell you, even those in areas hard hit by avian flu, the disease hasn’t affected all bird populations equally. After reading about the transgene solution, I checked in with my friend Jesse Narducci, who raises broilers and laying hens on pasture outside of Fairfield, Iowa. Despite this being a historic outbreak, he told me, he hasn’t had any problems with flu this year.

Tracking of the outbreak from the USDA Animal and Plant Health and Inspection Service would seem to back his experience up: It’s the birds that are kept in the most biosecure, enclosed, temperature-controlled facilities that are the most affected.

A USA Today story from May put the number of “backyard” infections at roughly 10 percent of those reported, which sounds like a lot. But there’s a very big difference between the number of reported incidents and the number of birds affected. According to the most recent USDA statistics, 20 out of 223 detections were found in “backyard” flocks, a term that, on the Animal and Plant Health Inspection Service website at least, includes mixed game fowl and pheasant flocks as large as 2,500 and 5,830 birds, respectively. For the majority of the backyard cases, figures for flock size are “pending,” but save for those large outliers, they range between 10 and nearly 600 birds. Of the commercial operations affected, the smallest was a flock of turkeys 4,200 strong, but many are in the six- and sometimes even seven-figure range. Even with the pending flock figures, the data shows that it is large commercial flocks that are the hardest hit—these are not the small, pasture-based operations of the world.

Since last December, more than 48 million birds have been affected. Iowa, the country’s leading egg producer, is home to 43 million hens alone.

While the number of affected chickens would appear to be staggeringly high—and disposing of all of the dead birds has been a challenge in its own right—the 341 million dozen-egg shortfall the USDA is predicting for this year will only represent a 4 percent decline in production. Though warmer summer temperatures have hampered the spread of avian flu, retail prices have continued to rise, with the average cost for a dozen large eggs topping out at $2.56 in the most recent market report from the USDA. (The three-year average is under $1.50 per dozen.)

If the virulent strain, H5N2, makes a return when temperatures dip lower, prices could hit $6 for a dozen eggs, as BB&T Capital Markets analyst Brett Hundley recently told NBC News.

If that does come to pass, the economic benefit of an industrial-scale egg industry—which enables it to persist in the face of the significant environmental and animal-welfare downsides to such concentrated product—would begin to fray.

So could stronger, healthier, hens raised outdoors supplant the current industry standard?

While the backyard birds may be less susceptible to avian flu—as well as other human public health concerns, such as salmonella—more space would be needed. According to Certified Humane standards, each bird needs 108 square feet of living space; a laying hen kept in a battery cage—the conditions in which more than 90 percent of the current commercial flock exist—has just 67 square inches of space. As a simple matter of real estate, Iowa’s flock would need more than 150 square miles of pasture to be transitioned to Certified Humane conditions, which is within the realm of possibility.

But with cage-free eggs being laid by just 5 percent of the commercial flock—despite the increasingly frequent announcements from major food companies that they’re going cage-free—there’s a long way to go between today’s status quo and the fantasy of a pasture-raised utopia.

Though if flu continues to kill off such large numbers of birds, the changes may start being propelled by the bottom line rather than environmental and welfare concerns.