William Owens, Jeong, Changyoon
William E. Owens and Changyoon Jeong
The poultry industry in Louisiana and across the nation has grown rapidly, and poultry is now the No. 1 animal commodity in Louisiana. Poultry generates approximately $2 billion for the Louisiana economy and is second only to forestry for all commodities. With this increase, challenges have arisen with the handling and disposal of poultry waste, which has become a major issue for the industry.
Poultry waste includes poultry manure, litter, hatchery and processing waste, and dead birds. In addition to the considerable cost and time producers invest in bird disposal, the resulting organic load poses a risk to the environment if not properly handled. Regulatory agencies are increasingly concerned with potential point-source pollution of groundwater from buried animal carcasses, including poultry. Recently proposed shallow burial methods may help protect ground water by keeping the organic matter farther from the water table.
The recent outbreak of highly pathogenic avian influenza (HPAI) and the subsequent loss of 50 million chickens and turkeys in the United States brought the difficulties in dealing with each catastrophic death loss to the forefront. Since it was first identified in the U.S. in the Pacific Northwest in December 2014, HPAI has been detected in commercial and backyard poultry flocks, wild birds and captive wild birds in 21 states. With the latest case of the spring outbreak identified in June 2015, a total of 211 commercial and 21 backyard poultry premises had been affected in the U.S. This resulted in the depopulation of 7.5 million turkeys and 42.1 million egg-laying and pullet chickens, with devastating effects on these businesses and a cost to federal taxpayers of more than $950 million.
While the recent outbreak served to highlight the difficulties of handling catastrophic losses in poultry, this problem has been a major issue in the poultry industry for years. Catastrophic loss or loss of an entire house or multiple houses of poultry can result not only from disease but from other events, such as power loss from storm damage or other mechanical failures.
When a major die-off occurs, exceptional procedures must be put in place to handle the excess mortality. Previously used methods to handle large numbers of dead birds include rendering, landfills, incineration, composting and burial. Rendering and landfills are restricted to locations near enough to existing facilities to be practical. Incineration requires special equipment and is costly. This leaves composting and burial as the most practical alternatives.
Burial has traditionally served as the most convenient method for disposing of large bird numbers. It has the advantage of being relatively low-cost and usually can be accomplished at or very near the site of loss. Burial pit dimensions and depths vary with state regulations and are also dictated by soil types and number of birds to be buried.
In the 2016 HPAI Preparedness and Response Plan prepared by the U.S. Department of Agriculture-Animal and Plant and Health Information Service, state partners were encouraged to assess their ability to perform depopulation and disposal of birds in the event of catastrophic losses. In Louisiana, the broiler demonstration houses at the AgCenter Hill Farm Research Station near Homer were selected to demonstrate shallow or above-ground burial of poultry after a simulated depopulation of a broiler facility. This project was initiated based on discussions with the Louisiana Department of Agriculture and Forestry and the USDA and coincided with plans at the Hill Farm to investigate above-ground burial methods as a means to handle poultry losses. The demonstration was coordinated with the poultry company House of Raeford Farms of Louisiana in Arcadia.
For the demonstration, two large trenches were dug, one for the test and one to serve as a control. The control trench had no air pipes and no wood shavings as a carbon source. The test trench had three rows of 4-inch sewer pipe with air holes and wood shavings as a carbon source. The test trench, fitted with 4-inch perforated sewer pipe to allow air access, reached temperatures above 120 degrees F by day 3, and temperatures remained between 105 and 110 degrees or above for approximately 50 days. The control trench with a similar bird load and no air or wood shavings had much lower temperatures. This trench reached a maximum of 104 degrees F but was below 100 degrees for the majority of the measured period. Periodic excavation of the two trenches revealed that decomposition in the trench with air access was greater than the control. The 4-inch sewer pipe and shallow burial allowed insects, primarily stone flies, access to the decomposing birds. Stone fly larvae are common in decomposing material and contribute greatly to decomposition of birds. Evaluation of trench temperature and core samples of trench material in September 2019 indicated that decomposition in the sewer pipe trench with air and wood shavings was essentially complete.
Results from the various trenches with and without air and shavings demonstrate that air and wood shavings greatly enhance bird decomposition. The shallow location of the trench allowed air and insects to enter the trench, resulting in rapid decomposition of birds. Wood shavings as a carbon source enhanced decomposition. This shallow burial design with air and wood shavings could prove to be a viable alternative to traditional deep burial for disposal of poultry. Further studies on a larger scale are needed to validate these methods.
William E. Owens is a professor at the Hill Farm Research Station in Homer, Louisiana. Changyoon Jeong is an assistant professor at the Red River Research Station in Bossier City, Louisiana.
(This article appears in the winter 2020 issue of Louisiana Agriculture.)
Test trench with 4-inch perforated pipes to allow air access. Photo by William E. Owens
Finished test trench covered with soil. Photo by William E. Owens