Project to slash chicken litter emissions to revolutionize industry from ground up
New floor and ventilation system would dry waste before it could produce ammonia
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That stink that comes from chicken houses? Blame moisture.
The naturally occurring moisture in chicken waste is what causes it to produce ammonia—and the stench that neighbors of poultry farms know well. One Maryland university is investing more than $3 million in a project to clean up chicken houses with a plastic flooring and ventilation system. Its creators say it could slash ammonia emissions that can sicken birds and leave neighbors holding their noses.
“This is like a revolution,” said Jeannine Harter-Dennis, a poultry science professor at the University of Maryland, Eastern Shore, which recently announced that it will spend $3.3 million in federal and state grants to develop the flooring.
The project is a new type of floor and ventilation system. Right now, chickens grown for food, called broilers, live in narrow houses on some type of bedding, usually wood chips or peanut hulls. The chickens excrete waste onto the bedding, which gets wet from the excrement. The nitrogen in the waste becomes ammonia, which poultry growers try to alleviate through electric-powered ventilation.
Too much ammonia gas in a chicken house can damage the broilers’ respiratory tracts or cause blindness.
The ammonia also stinks. Emissions from chicken houses are a common complaint in rural Maryland and other areas with large-scale poultry production.
Also, nitrogen deposition from air pollution is a major source of nutrients to the Bay, and ammonia emissions from agriculture have been a particular concern as they have been on the rise in the region, even as other sources of air pollution are starting to decline. The EPA is also considering new regulations on ammonia emissions.
Another environmental concern from poultry houses is the bedding itself. The waste mixes with the bedding to become litter or cake, which periodically must be cleaned out and disposed of, at a cost of about $1,000 per house for the farmer. Dirty bedding is a prime breeding ground for disease such as salmonella in the birds.
“It becomes a little mini compost pile,” Harter-Dennis said.
Salisbury engineer Rafael Correa came up with a flooring that could solve those problems. “This is a better bedding—a drier, healthier bedding,” he said.
Here’s how it works: A plastic mesh flooring is laid onto plastic cones, creating a surface about 4 inches off where a dirt floor would be. Chickens would stand on the plastic flooring, not wood chips, and excrete onto the plastic mesh.
Air would be forced from above through the mesh, drying the waste. Dry waste won’t produce ammonia because nitrogen in the excrement doesn’t become ammonia without moisture.
At the end of a growing season for a flock of broilers, poultry farmers would simply scrape dry manure off the plastic flooring and start again with fresh chicks. There would be no bedding, no wood whips or sawdust, to clean out and replace. Waste would be reduced about 80 percent, because it would be just the manure itself, not manure mixed with bedding.
“It’s a whole different concept,” said Douglas Green, a Princess Anne chicken farmer who has about 100,000 broilers and attended the university’s announcement last week. Green currently uses pine shavings and peanut hulls on the floors of his houses, spending about $4,000 a year for bedding removal.
“We’re constantly cleaning and taking the cake out,” Green said.
The university will test the flooring for about two years before it could be ready for widespread commercial use. It would cost farmers more at first to put in the new flooring—Harter-Dennis isn’t yet sure how much it would cost to retrofit a chicken house with the new flooring and ventilation. But after the new floor is installed, a poultry farmer’s expense on waste removal and ventilation would plummet.
“We’ve been calling it the poultry house of the future,” said Jim Rzepkowski, assistant secretary for the Maryland Department of Business and Economic Development. Poultry is the No. 1 agriculture product in Maryland, home of Salisbury-based Perdue Farms Inc., the nation’s third-largest poultry producer. The Delmarva Peninsula, which includes Delaware and Virginia’s Eastern Shore, produces 300 million chickens a year.
Researchers believe the flooring could save farmers money through lower electricity bills—because they would have more energy-efficient ventilation—and by boosting the health of the birds, improving survival rates and reducing infectious diseases spread through wet, dirty litter.
“This has the potential to improve grower profitability,’’ said Bill Satterfield, executive director of the Delmarva Poultry Industry Inc., an industry group. “One of the biggest costs growers have is the electricity bill. And it’s mostly related to ventilation.”
With a floor that cuts the need for traditional ventilation, Satterfield said, “the savings are significant.”
Harter-Dennis, who will start testing the flooring in a few university chicken houses this year, said the project could mean huge strides in the health of birds and the pollution caused by poultry production, both the ammonia gas emissions and the waste itself.
“It’s going to improve the environment. It’s going to improve bird health. It’s going to improve human health,” she said. “It’s going to just revolutionize the industry.
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