Science behind composting HPAI mortality

March 24, 2022

The need to depopulate a flock is the most difficult situation a farmer can face but is the best option to protect other healthy birds on the farm, and neighboring farms, from bird flu. Also challenging is the responsible and safe disposal of the euthanized birds. These choices are far more complicated when neighbors voice concerns about disposal near their homes.

USDA and other organizations state that properly implemented on-farm composting that reaches and sustains standard high compost temperatures is a safe and responsible way to manage these mortalities. The carcasses quickly decompose, and the virus is destroyed in the process. Below are science and government resources that can be shared with neighbors and the local community:

  • USDA’s Animal and Plant Health Inspection Service (APHIS) published guidance on composting mortalities in 2016 and reports that “Composting is a biological heating process that results in the natural degradation of organic resources (such as poultry carcasses) by microorganisms. Composting has been successfully used throughout the United States for nearly two decades to control outbreaks of low pathogenicity avian influenza (LPAI) and highly pathogenic avian influenza (HPAI). Composting can be effective with most bird types and poultry house designs.”
  • Research published 30 years ago in the Journal of Avian Diseases found that 95% (19 out of 20 tissue samples) of the HPAI were inactivated after the first 10 days of composting, and 100% was inactivated after the following 10 days of composting.
  • Research published in 2012 in the Journal of Applied Environmental Microbiology found that all of the strains of HPAI studied “were inactivated to levels below the detection limit within 24 hours from the start of the compost trial…and no infective particles of either virus could be found throughout the trial” and discussed that “on-site sanitization treatments such as composting are preferable….since transport of the material has been shown to be a risk factor for the spread of avian influenza between poultry farms.”
  • The International Journal of One Health confirmed similar findings in research published in 2017. That study found that common methods of compost handling “reached USDA protocol temperatures to neutralize the HPAI virus.”

State veterinarians and land grant universities have excellent resources on properly composting mortalities. See Iowa State’s 2017 publication “General Guidelines on Composting of HPAI Infected Carcasses.” Please get in touch with UEP for additional information and assistance on this topic.