How high is too high for a pile of chicken manure? Eight feet, apparently. Chicken waste is an excellent fertilizer, but with the growing season still weeks away it's piling up in barns across the South. To reduce the risk of fire from spontaneous combustion, poultry experts are warning farmers that piles 6½ to 7 feet high are high enough. One pile caught fire in western Arkansas this week, triggering a wildfire that destroyed a mobile home. "This hit the sweet spot," said Karl VanDevender, a professor and extension engineer for the University of Arkansas System Division of Agriculture, after describing the mix of moisture, texture, and decomposition needed to produce a burning pile of waste.
Normal composting at 130 to 145 degrees will kill pathogens, but extra moisture in the stack can help drive temperatures over 170 degrees, raising the risk of a fire, he said. "If you see smoke, it's kind of iffy. If you break in, you may introduce oxygen and set it off. Have water nearby," he said. The manure stack that caught fire Wednesday was 8 or 9 feet high. It set nearby hay ablaze and then flames jumped a highway and raced away on a steady 25 mph wind. It took about four hours to douse the flames; no one was injured. Arkansas is among the nation's leading poultry-producing states, with Georgia and Maryland, reports the AP.