Jay hardest-hit

Nine locations.

More than 4 million birds.

Jay County has been the hardest-hit state in Indiana by highly pathogenic avian influenza, commonly known as bird flu, with the most recent confirmed positive location this week.

Neighboring Mercer and Darke counties have been the hardest-hit in Ohio, with cases confirmed at 45 and 21 premises, respectively.

Adams County had one case in January with 19,860 birds affected at a commercial turkey operation.

The case confirmed Monday in Jay County affected 214,000 birds at a commercial egg layer operation, according to the Indiana State Board of Health. It was the ninth in the county this year, bringing the total number of birds affected to 4.23 million.

In each of the cases, the facilities have been “depopulated” — the birds have been euthanized — in an effort to stop the spread of the disease.

The most recent Mercer County case was confirmed Feb. 26, with 90,000 birds affected at a commercial egg layer facility. Darke County’s most recent case affected more than 3 million commercial egg layers, the largest Ohio operation to be hit with the disease this year.

All of the Mercer County cases have resulted in depopulation while the most recent Darke County case has a status of “ongoing” on the Ohio Division of Animal Health website.

In addition to depopulation, the Indiana Board of Animal Health’s response has also created a 10-kilometer “control area” and 20-kilometer “surveillance zone” around the affected facility. (Similar measures were taken in previous cases.) Surveillance zones from cases in Jay, Mercer and Darke counties currently impact Adams and Randolph counties as well.

Jay County had not experienced any cases of highly pathogenic avian influenza before 2025. It accounts for 61% of the birds affected in Indiana this year.

Nearly a quarter of Indiana’s cases — nine out of 40 — since the disease was confirmed in the United States in February 2022 have been in Jay County. (All nine have been identified this year.) Elkhart is the next hardest-hit with six cases, followed by Allen County with five and Dubois County with four. Adams and Randolph counties have each had the disease identified at one location.

The largest operation hit in Indiana thus far was a 2.6-million commercial egg layer operation in Jackson County. The positive confirmation there came on Jan. 28.

Mercer and Darke counties account for 66 of the 71 premises affected in Ohio this year and more than 98% of the birds affected (14.4 million out of 14.64 million). Darke County has the most birds affected at 8.3 million (56.8% of the Ohio total this year) while Mercer County has 6.08 million (41.5%).

According to the 2022 United States Department of Agriculture Census of Agriculture, Jay County ranks No. 2 in Indiana in the market value of poultry and eggs sold annually at $301.8 million. (That accounts for about half of the county’s total market value of agricultural products sold each year.) It is No. 1 in the state in total market value of agricultural products sold at more than $602 million annually.

The livestock inventory from the census showed Jay County has 9.8 million layers and nearly 600,000 turkeys. Those numbers are 5.8 million and 1.8 million, respectively, for Mercer County, with an additional 1.2 million pullets. 

Darke and Mercer counties rank No. 1 and 2, respectively, out of Ohio’s 88 counties in the market value of poultry and eggs sold annually. Darke County comes in at $636.2 million, with Mercer County at more than $494.3 million.

Highly pathogenic avian influenza has been identified at more than 1,300 locations since it was first confirmed in the United States three years ago.

Jay County Health Department’s role in dealing with the disease comes in the form of monitoring the humans who have come in contact with affected birds. When a case is reported to the state board of animal health, the Indiana Department of Health is notified with information then passed on to the county department. Individuals who have come in contact with affected birds are monitored for symptoms for 10 days.

“Hobby owners" should call the USDA Healthy Birds Hotline at (866) 536-7593 to report illness or death of poultry.