ST. LOUIS — Post Holdings, Inc. said a Michael Foods third-party egg-laying facility in Iowa has tested positive for highly pathogenic avian influenza (HPAI). Approximately 4.5 million egg-laying hens — approximately 12% of Post Holding’s controlled supply across owned and third-party contracted farms — are housed in the facility, according to the company.

The outbreak is one of the first reported incidents of avian influenza in the Midwest this season. Prior to this report, approximately 26 million egg laying hens have been lost to HPAI.

The virus has played a role in egg price volatility and impacted the overall egg supply.