Tackling cage-free layer housing air quality challenges
Giving laying hens access to a litter area for dustbathing, scratching and foraging helps minimize aggressive behavior, but it can result in dust and ammonia problems.
Aviary housing systems offer layers access to litter to express natural behaviors, such as scratching, foraging and dust bathing. However, air quality in cage-free systems may be compromised as dust (particulate matter) and ammonia increase as manure and litter accumulates on the floor.
Dust, which can serve as a carrier of microorganisms and endotoxins, is a significant health risk for both farm workers and the birds as fine particulate matter can enter into the respiratory system. Ammonia, likewise, can cause respiratory tract irritation or damage.
Dust control in cage-free houses
Recent studies have shown that cage-free housing results in six to nine times higher dust in the house environment than cage systems with manure belts. Researchers in Europe and the U.S. have explored many potential approaches to controlling dust including ionization with electrical charges using metal wires on the ceiling. Other studies have focused on spraying litter with treatments including tap water, acidic water, soybean, canola or rapeseed oil and combinations of water and oil.
Research at Iowa State University led by Drs. Hongwei Xin (project principal investigator, distinguished professor and director of the Egg Industry Center) and Lilong Chai (co-principal investigator and post-doctoral research associate) is now focusing on a control measure utilizing electrolyzed water supplemented with litter additives as needed.
Supported by promising results from laboratory trials, the research has now moved to a commercial layer farm using an aviary production system in Iowa. Electrolyzed water has been used in the food processing industry for many years. Sodium chloride is dissolved in tap water and subjected to an electrical charge. The dose of sodium chloride and duration of electrolysis in the reactor can be controlled to produce slightly acidic water with different concentrations of free chlorine. In the laboratory trials, Dr. Chai reports that “we have seen significant reduction in particulate matter and bacteria in the air and litter without causing increased ammonia levels.”