Poultry International - July 2017 - 22
22 ❙ PoultryInternational
How to mitigate dust and
ammonia in cage-free houses
A slew of novel technologies aiming to control dust and ammonia levels
inside cage-free houses are arriving to the market, but are they effective?
BY AUSTIN ALONZO
The free movement of hens in a cage-free system creates
dustier conditions and air quality issues inside the barn.
Cage-free farming brings inherent air quality challenges, so farmers need to adapt in order to protect the
health of their flock and their workers.
On April 20, Dr. Hongwei Xin, director of the Egg
Industry Center, spoke about the results of research surrounding devices and methods designed to mitigate airborne pollution inside cage-free layer houses and emissions coming from them. Xin, a distinguished professor
at Iowa State University's College of Agriculture and
Life Sciences, spoke as part of the Egg Industry Center
Issues Forum in Columbus, Ohio.
Roots of the issue
As the U.S. egg industry rapidly shifts from conventional cages and enriched cages to cage-free operations, more bird activity inside the house is leading to
increased airborne pollutants like dust and ammonia.
Simply, Xin said, birds are moving around in litter areas - scratching, foraging and dustbathing - as well
as flapping around the house stirring up dust. The hen's
freedom to move, and evacuate waste, wherever she
pleases is another challenge. This means the manure
belts in houses are no longer as effective as they once
were in collecting and drying waste to simplify disposal
and reduce ammonia emissions.
That raises the question of how farmers can mitigate
dust and ammonia levels that can harm the workers and
the birds. The issue, he said, should be examined in the
sense of indoor air quality - which affects hens and
farm workers, and emissions from the house - which
can raise issues with pollution and its impact on the environment and local ecosystems.
Reducing ammonia through
feeding and management
Xin said changing what the bird eats can affect the
amount of ammonia present in the house. He covered
the results of studies showing the efficacy of the following methods:
■ Reducing dietary protein: By reducing dietary proteins by about one percent and maintaining nutritional balance in the feed, farmers can reduce ammonia
emissions by about 10 percent. Dietary fibers reduce
the pH value of manure, meaning less ammonia is
mobilized from the manure.
■ Adding dietary fibers: Adding fiber, like wheat middling and soy hull, can reduce emissions from layer
manure between 40 and 45 percent.
www.WATTAgNet.com ❙ July 2017