Up until recently, Michigan — a net exporter of eggs and the seventh-largest egg-producing state in the country — had managed to avoid highly pathogenic avian influenza in commercial hen-laying operations.

Then, on April 3, a commercial flock of almost 2 million birds in Ionia County was confirmed positive at Herbruck’s Poultry Ranch, the largest poultry farm in the state.

Six days later, another location of Herbrucks in that same county was also found positive with just over 2 million birds.

Another commercial poultry operation has now tested positive for avian flu. The new location, confirmed April 16, is in West Michigan’s Newago County, housing 2,422,700 birds. While the disease has also spread to four dairy operations in Michigan, it is much more serious for the poultry industry, as all animals must be depopulated, and facilities completely sanitized before bringing in new birds. In total, 6,498,700 birds are affected by the outbreak.

Avian flu, which is generally carried by wild birds such as ducks and geese, is highly contagious. It’s also extremely lethal. It kills 90% to 100% of chickens, often within 48 hours, according to the Centers for Disease Control. Once the virus is detected, the whole flock must be depopulated, according to a federal mandate.

The disease remains a wild card in poultry production, holding on longer than the 2014-15 outbreak that subsided over the summer months. 

On April 2, Texas had a commercial egg-layer operation of just under 1.9 million birds test positive.

Since the start of the outbreak, Feb. 8, 2022, 90.6 million birds have been affected nationwide — 1,125 flocks in 48 states, including 480 commercial flocks.

Dairy infection

The April flock announcements came just a few days after bird flu was detected in a Michigan dairy herd in Montcalm County, which received animals from a HPAI-positive Texas herd, according to USDA’s National Veterinary Services Laboratories (NVSL).

The disease causes cows to have decreased lactation, low appetite and other symptoms, but it does not require them to be euthanized. Cows are removed from the milking herd and treated.

On April 13, avian flu was confirmed in dairy herds across three more West Michigan counties, according to the Michigan Department of Agriculture and Rural Development.

In addition to Michigan, from March 25 to April 15, USDA has confirmed the detection of HPAI in dairy herds in Texas (11), Kansas (3) and New Mexico (6), as well as one herd each in Ohio, Idaho, South Dakota and North Carolina, according to NVSL website.

Wild migratory birds are believed to be the source of infection. However, the spread of the illness among the Michigan herd also indicates that HPAI transmission between cattle cannot be ruled out, NVSL reports.

“This virus does not stop at county or state lines, which is why we must all be on high alert,” MDARD Director Tim Boring said in a news release. “This news is unfortunate and upsetting for our poultry and dairy farming families and communities.”

One human case of HPAI was reported in Texas. The strain of the virus found in Michigan is similar to the strain confirmed in Texas and Kansas, according to NVSL. Initial testing has not found changes, or mutations, to the virus that would make it more transmissible to humans.

“This infection does not change the A[H5N1] bird flu human health risk assessment for the U.S. general public, which CDC considers to be low,” the NVSL advises. “However, people with close or prolonged, unprotected exposures to infected birds or other animals [including livestock], or to environments contaminated by infected birds or other animals, are at greater risk of infection. While cases among humans in direct contact with infected animals are possible, the current risk to the public remains low.”

Michigan losses

It’s not to say Michigan had not been harmed by the disease, but in comparison to other states, it was keeping the infection rate reasonably low — until recently. The state had its first commercial operation test positive on May 10, 2022, with 35,100 turkeys needing to be depopulated.

Michigan then went a year and half with no commercial operations testing positive up until December 2023, when two commercial turkey operations — both in Muskegon County — tested positive on Dec. 19 with 47,900 birds, and Dec. 27 with 31,500 birds. In total, from the first backyard flock outbreak in Michigan on Feb. 23, 2022, the state has had 31 outbreaks accounting for 6,498,700 birds.

“Herbruck’s is heartbroken by the loss of any hen, and we were devastated to learn that some of the hens at our Green Meadow Organics facility are infected with highly pathogenic avian influenza,” Greg Herbruck, CEO of Herbruck’s Poultry Ranch, said in a statement.

“Our company veterinarian noticed sick birds at the facility, and lab results confirmed our fears that avian influenza was present. Our team worked quickly to implement protocols to protect the rest of our flocks — along with our long-standing biosecurity measures — including prohibiting movement between our Green Meadow Organics facility and other sites. We remain committed to protecting the rest of our flocks and keeping our team members and customers informed during this challenging time, as we work as quickly and safely as possible to disinfect and begin production again at this farm.”

Herbrucks, a generational family farm, has a flock of 10 million birds across facilities in Michigan, Indiana and Pennsylvania. It supplies eggs to grocery stores across the Midwest and is also a major supplier to McDonald’s.

Other HPAI developments