In the USA, cage-free (CF) housing systems have gained popularity as an ethical and humane poultry farming method. However, the concentration of air pollutants inside CF housing, particularly regarding dust or particulate matter (PM), poses a major concern on animals and their caretakers. These air pollutants can threaten bird health and worker safety. Various studies have shown that birds exposed to these air pollutants experienced negative effects on health and welfare and increased mortality rates. Exposure to high air pollutant levels can result in respiratory issues and decrease productivity in laying hens. Moreover, farm workers exposed to these air pollutants are at higher risk of developing chronic respiratory diseases like bronchitis, asthma, and airway obstruction. The presence of air pollutants in the air not only endangers the safety, health, productivity, and behavior of the animals but also causes significant damage to the surrounding ecosystem and contributes to the formation of regional haze. Therefore, implementing an effective mitigation strategy can help reduce air pollutants and the adverse effects caused by their emissions.

Researchers at the University of Georgia’s poultry science department proposed the electrostatic particle ionization (EPI) technology for dust reduction (Figure 1). The EPI system has been tested as an effective solution for reducing air pollutant emissions in broiler houses.

Figure 1. Working mechanism of EPI systems in cage-free hen houses. EPI- electrostatic particle ionization; PM- particulate matter.

The EPI technology uses an electric charge to attract and capture PM particles and associated NH3 molecules, causing them to cluster and form larger particles or molecules in the air. In this research, the Latin Square Design (LSD) method was employed due to the limited availability of rooms, specifically four experimental CF rooms, to conduct the four treatments across four trials. Each Trial lasted one week, after which the EPI systems were thoroughly cleaned. The EPI systems operated continuously for 24 hours during each Trial. The varying lengths used in the study provide valuable insights into the specific spacing approaches utilized in previous research. The EPI systems were positioned at 8 feet instead of the standard 9-foot height in our experimental CF rooms. This adjustment was necessary to accommodate room equipment, such as heaters, circulating fans, and water supply pipes. A challenge for using EPI system is birds’ perching. To address that, we installed bird-repellent spikes above the corona pipe using adhesive glue to prevent hens from perching on the corona pipes. Maintaining a minimum distance of 1 foot between the EPI system and the ceiling and walls is important to avoid any electric field effects on nearby objects. The corona pipes were positioned 1 foot (0.3 m) away from the side walls and 8 feet (2.4 m) away from the front and back walls, with a gap between the corona pipes, as depicted in Figure 2.

Figure 2. Experimental setup for EPI system in cage-free hen housing. EPI- electrostatic particle ionization.

According to the test, the dust levels was reduced by up to 33% by EPI system. This study provides a practical solution for reducing dust in CF hen houses. Using longer corona pipes, we improved air quality further. Implementing EPI systems does come with challenges and costs, requiring regular cleaning and maintenance for optimal operation. Future research should focus on enhancing EPI technology, evaluating its impact on chicken health and productivity, and assessing its cost-effectiveness on a larger scale. Exploring combinations with other mitigation strategies may yield even greater reductions in PM concentrations. Continued research and development of EPI systems will contribute to improved air quality control in poultry production, promoting bird welfare and minimizing environmental impact while striving for sustainable and responsible practices in animal agriculture.

Further reading:

Bist, R. B., Yang, X., Subedi, S., Ritz, C. W., Kim, W. K., & Chai, L. (2024). Electrostatic particle ionization for suppressing air pollutants in cage-free layer facilities. Poultry Science, 103494.