Rodents Among Several Culprits in Avian Flu

As the U.S. poultry industry begins a slow recovery from what some are calling the worst outbreak of avian flu the country has ever experienced, the USDA, recently announced that rodent presence in poultry houses, as well as sharing of equipment between infected and non-infected farms, were among several causes behind the spread of the virus.

The federal government expects to spend $191 million to pay chicken and turkey farmers for birds lost to avian flu according to U.S. Secretary of Agriculture Tom Vilsack, who says that’s in addition to the nearly $400 million spent on cleaning up dead birds and disinfecting barns. The government also is paying to research and stockpile a bird flu vaccine.

Commercial poultry facilities are an ideal rodent habitat as they provide everything they need to survive and thrive, such as unlimited amounts of food, water, and shelter. Furthermore, because of their habits such as contact with garbage and sewer systems, rodents can intensify or accelerate disease outbreaks with their droppings, fur, urine, or saliva. Lastly, rodent presence in food sources results in major losses with some experts estimating that these pests destroy enough food each year to feed 200 million people.

As several rodent species, including the house mouse, Norway rat, and roof rat are commonly found in and around farms, it’s imperative poultry farmers know how to control these species to prevent spread of disease, such as the avian flu, and contamination of poultry and eggs.

Finding the Rodents
Infestations often can go unnoticed because rodents living in farm facilities tend to be most active just after dusk and right before dawn. But since mice produce between 30 to 100 droppings a day and rats about 30 to 50, droppings are one of the most common signs of an infestation.

Before implementing rodent-proofing methods, it’s important to conduct regular, visual inspections of the premises for droppings, tracks, burrows, pathways, fresh gnaw marks, as well as live and/or dead rodents. If rodents are seen repeatedly during the day, it indicates an established infestation. According to the Mississippi State University Extension Service, there are fairly reliable guides to determine rodent populations, which include:

• Observed signs, but no rodents seen: 1 to 100 on the premises;
• Occasional sightings at night: 100 to 500 on the premises;
• Nightly sightings and occasional daytime sightings: 500 to 1,000 on the premises; and
• Several seen during the day: up to 5,000 on the premises.

Rodent-Proofing Poultry Facilities
As noted in the USDA avian flu report, cross-contamination of equipment and rodent presence were partially responsible for the transmission of the virus, placing even greater significance on sanitation and maintenance of poultry houses. Considering most rodents enter the barn directly from the fields, it’s important to eliminate any vegetation within a 3-foot area around buildings they can use as hiding spots. Additionally, poultry farm personnel should clean up spilled feed on a regular basis, keep all feeds in rodent-proof bins or covered cans, remove loose wood and garbage, and eliminate any areas that can be used by rodents as hiding and nesting spots, such as loosely piled building materials or old feed bags.

Similarly, farmers should regularly inspect the premises for cracks around door frames, under doors, broken windows, water and utility hookups, and vents and holes surrounding feed augers as all can be used by rodents to gain entry into the facility. It’s advisable to use coarse steel wool, hardware cloth, or sheet metal to cover any entrances instead of plastic, wood, or insulation since rodents can easily gnaw through such materials. In addition, after eliminating food and shelter, farmers need to eliminate water sources such as leaky taps, open water troughs, and open drains. Without readily available food and water, rodent populations cannot expand.