The biggest avian flu outbreak yet — 5.3 million chickens — was confirmed Monday at an Iowa egg-laying operation, while Hormel Foods Corp. announced that flu-related bird losses will reduce its turkey production, putting pressure on profits.

The flu touched down in Osceola County, just southwest of Worthington, Minn., the first outbreak in Iowa’s egg industry, which is the nation’s largest. With 5.3 million hens set to die, the bird loss is massive — three times the combined 1.7 million turkey fatalities on 28 stricken Minnesota farms. Prior to this, the largest outbreak affected 310,000 at a Hormel-owned turkey farm in Meeker County.

“This is a large farm in Iowa, but not the largest,” said Randy Olson, executive director of the Iowa Poultry Association. Iowa has about 30 large egg operations, and the state has about 58 million hens. Thus, the Osceola farm represents about 9 percent of Iowa’s hen population.

The bird flu, which has ripped through Minnesota’s turkey industry, hit Iowa for the first time last week when it was reported at a turkey farm there. Iowa’s much bigger egg industry has been upping its biosecurity defenses. “It’s not surprising we are seeing highly pathogenic avian influenza in our state,” Olson said. “But it’s still very concerning.”

The U.S. Department of Agriculture also reported Monday that two more Minnesota farms, with a total of 31,000 birds, have been stung by the bird flu. The two outbreaks were the sixth and seventh in Kandiyohi, Minnesota’s biggest turkey-producing county.

Minnesota, the nation’s largest turkey producer, has been the epicenter of the H5N2 outbreak and Austin-based Hormel has been hit hard, as it relies on this state and Wisconsin for its birds.

Of the 28 Minnesota farms stricken by the flu, 18 have been suppliers to Hormel’s Jennie-O turkey division. Some of those are run by contract farmers or independent farmers; others are directly owned by Hormel. Also, a Hormel-owned farm in western Wisconsin with 126,700 turkeys was hit by bird flu last week.

“We are experiencing significant challenges in our turkey supply chain due to the recent [highly pathogenic avian flu] outbreaks in Minnesota and Wisconsin,” Hormel CEO Jeffrey Ettinger said in a statement. Owner of the Jennie-O brand, Hormel is the country’s second-largest turkey processor.

“While Jennie-O Turkey Store has delivered strong financial performance so far in the first half [of Hormel’s fiscal year], tight meat supplies and operational challenges will pressure earnings in the back half of our fiscal year,” Ettinger said.

Hormel maintained its per-share earnings outlook of $2.50 to $2.60 for the year, but said that because of turkey supply woes, profits will likely fall on the lower end of that range. Hormel’s announcement was made after the stock market closed. Its shares were down almost 1 percent in after-market trading.

Turkeys are particularly susceptible to highly pathogenic H5N2 flu. But an egg-laying operation with 200,000 hens in eastern Wisconsin was stricken a week ago, and a commercial chicken farm in California was hit in February.

The virus can kill a barn filled with thousands of birds in a couple of days. But the majority are euthanized out of precaution, a government policy to stop the disease from spreading.

Bird flu is believed to be emanate from migrating waterfowl that carry the disease, but don’t get sick from it. The virus is shed through waterfowl feces, and is somehow infiltrating poultry farms.

Health experts say bird flu is not a food safety hazard, and the low risk it poses to humans is primarily to farm employees who work with infected birds. None of those workers have been reported sickened in the United States.

Also on Monday, Wisconsin Gov. Scott Walker declared a state of emergency there, authorizing the Wisconsin National Guard to assist authorities responding to the bird flu in Jefferson, Juneau and Barron counties. That includes helping with the response and cleaning up once the birds are killed.