Commercially raised chickens can take only so much heat.

This summer's back-to-back weeks with temperatures above 100 degrees have proved challenging for poultry farmers and processors in Arkansas and eastern Oklahoma who have worked to keep the animals alive.

More than 250,000 dead chickens were disposed of in Arkansas in June and July — four times the reported number for the same months in 2010. Farmers and academics say the number could have been much higher without today's chicken-house technology that helps keep the birds cool.

The excessive heat comes at a time when the industry is self-correcting for an over- supply of chicken. It has closed plants, consolidated operations and lengthened the amount of time between deliveries of day-old chicks.

This year, poultry producers in Arkansas and Oklahoma experienced one of the hottest July's on record. Data from the National Oceanic and Atmospheric Administration confirm that Arkansas had its fourth-hottest July since such record-keeping started in 1895. Oklahoma, which is experiencing one of its driest summers, had its hottest July.

On farms, reports of equipment malfunctions and dry wells have contributed to some of the reported bird deaths. That doesn't take into account the number of chickens that die en route to processing plants. This year's triple-digit heat prompted at least one processor to stop trucking the birds.

Keeping the fowl cool and alive in hot weather involves a balance of temperature, relative humidity, air flow and body mass, say experts such as Robert Wideman Jr., an associate director of the University of Arkansas' Center of Excellence for Poultry Science in Fayetteville.

Wideman said there's no specific temperature that can be singled out for heat deaths in chickens. But generally a chicken can stand a higher temperature on a drier day, Wideman said.

A chicken cannot sweat, and its feathers can act as insulation. The animals cool themselves through panting and extending their wings, he said.

Technology has minimized many heat-related deaths throughout the industry.

It "still occurs but has been greatly diminished," said Richard Lobb, a spokesman for the Washington, D.C.-based National Chicken Council, the industry's national trade group.

Industry experts say "tunnel houses," which are outfitted with so-called cool-cell technology, can maintain 20-degree differences between the structures' interiors and exteriors.

Cool-cell technology, introduced in the mid-1980s, uses water mist and powerful, shed length air movement to keep the interiors cool.

When it's hot for weeks on end, however, the weakest birds will perish at lower humidity, experts say.

Ted Hostetler, a Mennonite trucker who specializes in hauling poultry litter and who is in charge of overseeing the Mennonite Disaster Service, said that while equipment and technology have improved tremendously over the past 20 years, malfunctions seem to happen every year.

Hostetler who can get the help of the 50 Mennonite families that settled Carroll County in 1982, reported that his organization disposed of more than 80,000 birds in Carroll and Boone counties this July.

A water-switch failure contributed to the deaths of 60,000 birds and the remainder perished because houses weren't equipped with the water-cooling technology, he said.

"There's no question that this summer has been one of the worst," Hostetler said. "It's had the most numerous days of more than 100-degree heat. And it's unusual for Northwest Arkansas to have that hot of a temperature for" so many days.

Kenneth Keeland of Berryville is one of 1,600 Tyson Foods contract farmers in the state. He said he watches his flocks closely during hot weather because of a greater chance of equipment failure.

"The tunnel houses make it easier to take care of the birds as far as keeping them cool, but it's definitely harder on the nerves," he said.

Tyson Foods Inc. of Springdale, the nation's largest poultry producer, said birds in modernized poultry houses tend to fare better in the summer heat as compared with chickens in older style houses.

While the company acknowledged losing some birds because of the weather, "our chickens are raised indoors by contract family farmers who operate chicken houses designed to protect the birds from temperature extremes," Worth Sparkman, a Tyson spokesman, wrote in an e-mail.

The company declined to provide a breakout of the number of farmers operating modern houses, in comparison with those that do not.

The National Chicken Council doesn't have an average statistic for birds that die because of the heat every year. Instead, growers across all weight categories can expect to lose as much as 4.5 percent of every flock during any season.

Death rates related to truck transportation are kept and tracked by individual companies. The number of chickens that are dead on arrival is kept to less than half of 1 percent per week, said the chicken council's Lobb who was unable to provide any more context for that statistic.

The council estimates that processors invest 25 cents per bird, or a nickel per pound, while the chickens are on the farm.

An average chicken will weigh 5 pounds and average 42 days to reach that weight.

In Arkansas, the Livestock and Poultry Commission emergency disposal permits offer a glimpse at reported chicken deaths.

Farmers say the companies normally get the permits.

Dewayne Kimbrell, agency director for the commission, said companies and growers report the mortality figures in good faith.

"It's been an extraordinary summer for hot weather," he said, "and the growers do an exceptional job in managing their flocks and taking care of them."

Kevin McDaniel, vice president of production with O.K. Farms Inc. in Fort Smith, said the majority of heat-related problems for his company happened on farms in Oklahoma.

"The number of days over 100 degrees depleted the water supply so that we had to employ tanker trucks to replenish the supply," he said.

The privately held company on the Arkansas-Oklahoma border contracts with 370 farmers, of whom more than 98 percent have houses with cool-cell technology, and operates two plants: one in Fort Smith and another an hour south in Heavener, Okla.

The high temperatures not only worsened drought conditions in both states, but forced O.K. Farms' parent company to modify its bird-delivery schedule.

During the worst of the heat wave, keeping the chickens out of the heat became a priority.

The company, which runs a four-day-a-week operation, halted deliveries from 4 p.m. to 7 p.m. and compensated for the reduction by operating on Fridays and Saturdays, he said.

At the plants, caged birds waiting to be processed are parked alongside fans and misters. Birds also are fanned and misted when being loaded at the farm.

"There's so much cost in them that we didn't want to lose those birds on the way to the plant," McDaniel said.

Marvin Childers, president of the Poultry Federation, a tristate organization representing the industry in Arkansas, Missouri and Oklahoma, said it's in the company's best interest to keep the animals healthy and alive.

But "the heat's been wicked," he said. "And it's been very tough at the farm level."


Information from: Arkansas Democrat-Gazette,