Switchgrass: Better Bedding for Broilers?

Pamela Porter
Newsletter Issue: 
April 2015

Crowd of chickens
Photo credit: 
U.S. Department of Agriculture 
(Poultry Classes Blog photo) 
CC BY 2.0 Wikimedia Commons 

Delaware is big on birds. The tiny state ranks 49th in land size but 10th in pounds of meat chickens produced. Delaware’s Delmarva Peninsula, located between the Atlantic Ocean and the Chesapeake Bay, has some of the country’s largest poultry processing companies including Tyson, Perdue, Amick and Mountaire Farms. Bedding for these birds, traditionally pine shavings and sawdust, is big business.

In 2008 when the housing market plummeted, the Delmarva Peninsula lost nearly 50% of their board lumber mills. Poultry producers lost their local source of affordable, pine-based bedding materials. Bill Brown, University of Delaware’s Poultry Extension Agent had heard that researchers in North Carolina and Georgia were testing miscanthus grass as an alternative to pine shavings. He wondered, why not bed with switchgrass?

“We had a scarcity and a price issue,” said Brown. “The poultry houses were bringing in cocoa hulls from Hershey, Pennsylvania and peanut shells from Virginia.”

Brown had heard that the Nature Conservancy and the Chester River Association, two environmental organizations, had teamed with area farmers to plant 500 acres of switchgrass. They were looking for buyers. The non-profits, working to improve the water quality of the Chester River, a major tributary of the Chesapeake Bay, had hoped to gain entry into the biofuels market, and the interest of dairy farmers, with the conservation crop.

“We’re at sea level here and have a lot of low areas that are wet and marginal in terms of productivity, said Mike Dryden, Project Coordinator for the Nature Conservancy. “We pay for seed and $200 an acre [each year] for three years to grow switchgrass. The farmer plants and harvests it.”

But the trouble was the biofuel market wasn’t developing readily and farmers were planning to turn back to row crops.

“Paul Spies [of the Chester River Association] and I got talking,” said Brown. “We thought that if we could grind the switchgrass down fine enough, it might make a good bedding material. “

Brown’s 30 years of experience in the poultry industry enabled him to forge partnerships with Perdue and Amick’s, among the country’s largest poultry processing companies, and soon the University of Delaware’s alternative bedding test was underway.

It was a learning experience. Brown started with tub grinders, round grinders commonly used to chop baled hay and mix livestock feeds, but they produced an unevenly sized product and were a disappointment. Then he found Rotochopper, a Minnesota based manufacturer specializing in horizontal wood grinders for mulch, compost and animal bedding. The company’s grinders offer a range of screen sizes, enabling greater selectivity in particle size control.

Brown learned that Rotochopper were custom grinding dairy feed in Lancaster, a couple hours away, and was willing to truck the equipment in for a test grind. The Rotochopper grinder test was set up at a Perdue poultry house in Delmarva.

“It’s a huge piece of equipment,” said Brown. “They came 75 miles out of their normal area to do the project.”

Brown liked what he saw. The Rotochopper grinder produced evenly sized, high-quality bedding and shattered the thick, switchgrass stem. Bedding uniformity is critical in poultry houses. With irregularly sized bedding, the feet and pecking behavior of chickens causes smaller “fines” (particles from the grind), to sift down to the floor while larger pieces rise to the top locking together and sealing wet bedding (a process often called crusting). Wet bedding conditions can lead to higher bacteria and disease levels, insect problems and feet lesions.

Participating farmers delivered the switchgrass a truckload at a time to be ground with the Rotochopper using a 1 1/4” screen. The ground switchgrass was then spread into 4 of the poultry houses at a rate of 0.67 tons per 1000ft2 (approximately 3” deep). Another 4 houses received pine shavings. To minimize variability, birds from the same family were used and divided into the eight houses.

Birds were evaluated for weight gain, feed conversion, livability and costs. The quality of chicken feet, an Asian delicacy and a significant U.S. export market, was also evaluated.

The results showed that chickens bedded with switchgrass were equal in weight, feed conversion and mortality to birds bedded with pine shavings. Initially, foot quality of chickens raised in switchgrass straw showed no difference from birds raised in pine shavings however some of the poultry houses experienced wet bedding issues.

The biggest draw was economics. The cost to mow, bale, transport and process switchgrass was $2,345 per poultry house (spread at 3” depth of bedding) compared to $2,750 for pine shavings, a 15% savings. An average size poultry house (about 20,000ft2) required 13.4 tons of switchgrass. At 3 tons of switchgrass per acre, this meant that each poultry house bedded with switchgrass supported 4.5 acres of switchgrass on the ground. With a higher yielding bioenergy grass, like CenUSA’s ‘Liberty,’ these costs could be reduced significantly, making switchgrass even more competitive with pine shavings.

Brown was pleased with the results. “We partnered with Perdue and have proven we can grow chickens very successfully bedded with switchgrass if its handled properly.”

Mike Dryden agreed, “We’re hopeful that with the poultry industry’s help, the door is going to open and you’ll see switchgrass become a popular crop.”

Perdue has expressed an interest in bedding a percentage of their houses with switchgrass and is reviewing a proposal from the Nature Conservancy to ramp up switchgrass production. If a business venture can be forged, poultry producers on the eastern seaboard will have a new bedding source and farmers will have a new market. The biggest winner? Agricultural producers who will have a market-based method for improving water quality in the Chesapeake Bay watershed.