Agricultural and Biosystems Engineering Publications

Campus Units

Agricultural and Biosystems Engineering, Animal Science, Egg Industry Center

Document Type


Publication Version

Accepted Manuscript

Publication Date


Journal or Book Title

Transactions of the ASABE

Research Focus Area(s)

Animal Production Systems Engineering




Compared to conventional cage production systems, cage-free (CF) hen housing offers hens more space and opportunities to exercise their natural behaviors (e.g., perching, dust bathing, and foraging). However, CF housing poses a number of inherent environmental challenges, among which are high levels of particulate matter (PM) and ammonia (NH3). Spraying water on CF henhouse litter (e.g., 125 mL m-2 per cm litter depth) has been shown to mitigate generation of PM by 60-70% in our previous lab-scale tests. The objectives of this study were to verify the lab-study findings of PM reduction in a commercial CF henhouse in central Iowa and to evaluate the indoor air quality (e.g., PM and NH3 concentrations) and litter moisture content affected by water spray. The commercial CF house had a nominal capacity of 50,000 laying hens, measuring L×W×H = 154 × 21.3 × 3.0 m). A water sprinkling system was installed in half of the henhouse in the length direction (treatment section), whereas the other half of the henhouse served as the control. For each of the three trials conducted during winter of 2017-2018, spray dosage (125 mL H2O m-2 per cm litter depth) was set according to the initial litter depth before spray. Results show that PM concentration was reduced by 37-51% PM in the treatment section of the CF henhouse. The lower reduction efficiency in the field than in the lab tests was partially attributed to the fact that water spray in the commercial henhouse was applied to only the open litter area, and not the litter area under the aviary system due to limited space. Adjusting spray dosage according to litter depth is necessary for maintaining the appreciable reduction efficiency. Litter moisture content of the treatment section was 9-14% higher than that of the control (15.6% vs. 14% in Trial 1, 14.6% vs. 12.2% in Trial 2, and 17.7% vs. 14.9% in Trial 3), but NH3 concentrations in the treatment and control sections were similar during the test.


This is a manuscript of an article published as Chai, Lilong, Hongwei Xin, Yu Wang, Jofran Oliveira, Kailao Wang, and Yang Zhao. "Mitigating Particulate Matter Generations in a Commercial Cage-free Henhouse." Transactions of the ASABE (2019). DOI: 10.13031/trans.12982. Posted with permission.

Copyright Owner

American Society of Agricultural and Biological Engineers



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Published Version