‘Real World’ Experience with New Poultry Depopulation Method

CHARLENE M. SHUPP ESPENSHADE
Special Sections Editor

MANHEIM, Pa. — On April Fool’s Day, April 1, at 8:30 in the evening, University of Delaware Poultry Specialist George “Bud” Malone received a phone call. A turkey farm in West Virginia confirmed the H5N2 Avian Influenza (A.I.) strain on the farm. Could he please bring his equipment to foam the house for depopulation.

This was not an April Fool’s joke, but a chance for Malone and others to earn some “real world” experience with a new technology for depopulation — foaming a house.

Malone addressed the April meeting of the Poultry Management and Health Seminar at Kreider’s Restaurant here Monday.

At hand for depopulation were four houses — two with 10,000 birds, one with 3,000 birds and one with 2,000 birds. Through this experience, Malone said a lot of lessons have been learned for bringing this application to the real world.

Foaming of a poultry house is a relatively new idea, getting its beginnings at the University of Delaware in 2004. The foaming concept involves fire fighting-type foams, including high expansion, compressed air foam, Class A and other foams. Research discovered that the foam can be successfully used to depopulate birds.

The foam is placed in the houses by a couple of methods, including moveable foam generators, stationary foam generators and portable hose and nozzle lines.

These studies have shown that foams are comparable to the carbon dioxide (CO2) polyethylene tent procedure in time-to-death in small groups. The foam is faster as group size increases. Adding carbon dioxide to the foam does not enhance its efficacy. Based on corticosterone levels, the study also showed that the foams are no more stressful than depopulation with the polyethylene tent method.

Malone said there was no evidence of drowning in any of the foamed birds. Foam caused an airway occlusion. The foam acts by physically induced hypoxia (shortage of oxygen).

The foam method for depopulation was recently approved by USDA.

The first challenge Malone encountered was since the call came on a Sunday, he was unable to get permission to pull the foam generator, owned by the Delaware Department of Agriculture, out of state. Fortunately, the manufacturing company owner who developed a foam generator had an available unit and agreed to travel with Malone to the farm.

A North Carolina depopulation team was also contacted and brought nozzle foam equipment to assist. The North Carolina team struggled with their equipment, facing some foam quality issues, pump failures and worker fatigue because of the delays. Because of the poor foam quality, water leaching from the barn became an issue.

Foam quality challenged even Malone’s team since there was not a consistent single brand of foam. One foam, he said, was 20 years old and had “sludge” in the bottom of the container.

With foam, consistency is critical to get the needed height to cover the birds and ensure death. Also if the foam bubbles are too big or too small, it will not work.

Water to make the foam is dumped into a vat system. The problem for both systems was making sure the foam concentrate to water ratio remained at 1 percent. Malone believes this real world trial will send some companies back to the drawing board to develop an in-line injection system to maintain the needed concentrations.

It is essential to get complete floor coverage in the barns when foaming. With the foam generator, Malone said his team did not get far enough into the barns to make sure the corners were fully covered. Also, for the people operating the generator, a communication system is needed. As the operator on the outside of the barn pulls the unit, the unit operator needs to be able to tell them if they need to speed up or slow down.

More work is also needed to ensure proper human safety. It was recommended there be one employee responsible for human safety on the site because everyone else is focused on the birds. Malone said more work is needed on the foam generator system to help pull the generator out of the barn without it getting stuck on bird carcasses.

Despite the challenges, Malone called the depopulation a success and was “pleased with the results.” The main goal is now fine-tuning the process based on what has learned.

Within a couple of hours of foaming the birds, the composting crews were able to move into the house and begin the composting process.

The benefits of this system is that the animals are more humanely depopulated with a quicker kill time and increased worker protection. The farm can move more quickly into composting of the birds.

The key recommendations Malone makes is that states need to enter into reciprocal agreements for faster response time for outbreaks. Also, response teams need to continue to get training to improve the process and foam accessibility is critical.

It was noted that the Pennsylvania Department of Agriculture is looking to purchase a foam generator. Also, Penn State is partnering with the University of Delaware for further work on foam methods of depopulations.