Mitigating Particulate Matter Generation in a Commercial Cage-Free Hen House

Abstract

Abstract. 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 hen house litter (e.g., 125 mL m-2 per cm of litter depth) has been shown to mitigate generation of PM by 60% to 70% in our previous lab-scale tests. The objectives of this study were to verify the lab-scale findings of PM reduction in a commercial CF hen house in central Iowa and to evaluate the indoor air quality (e.g., PM and NH3 concentrations) and litter moisture content as affected by water spray. The commercial CF house had a nominal capacity of 50,000 laying hens and measured 154 m × 21.3 m × 3.0 m (L × W × H). A water sprinkling system was installed in half of the hen house in the length direction (treatment section), while the other half of the hen house served as the control. For each of the three trials conducted during the winter of 2017-2018, spray dosage (125 mL H2O m-2 per cm of litter depth) was set according to the initial litter depth before spraying. Results show that PM concentration was reduced by 37% to 51% in the treatment section of the CF hen house. The lower reduction efficiency in the field experiment than in the lab-scale tests was partially attributed to the fact that water spray in the commercial hen house was applied only to the open litter area, and not the litter area under the aviary system, due to limited space. Adjusting the spray dosage according to litter depth is necessary for maintaining an appreciable reduction efficiency. Litter moisture content in the treatment section was 9% to 14% higher than in the control section (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 field experiment. Keywords: Air quality, Alternative hen housing, Dust, Litter moisture content.

Review of Measures to Control Airborne Pollutants in Broiler Housing

“…In broiler housing, the PM consists of a complex mixture of solid and liquid materials such as litter materials, feathers, feeds, skin, excreta, dander and microorganism, whit about 90% organic content [41]. The classification of PM is based on particle size (aerodynamic diameter), considering PM 1.0 (≤1.0 μm), PM 2.5 (≤2.5 μm), PM 4.0 (≤4.0 μm), PM 10.0 (≤10.0 μm) and total suspended particle (TSP) (≤100.0 μm) [42]. The PM emissions from broiler housing are affected by various factors and change according to housing system or types, litter materials, diurnal and seasonal variation, ventilation system and velocity, temperature and relative humidity, birds age and type, activity and stocking density and manure management (Figure 2) [41].…”

A Machine Vision-Based Method for Monitoring Broiler Chicken Floor Distribution

“…The "eYeNamic" system, for instance, evaluates a gait score based on a group activity index quantified according to pixel changes in continuously recorded photos/videos. The broiler house is a physically challenging environment for vision-based monitoring due to equipment interference and dust levels [35,36], and usually leads to poor image quality and results. In the long-term, we plan to develop a mobile imaging system equipped with a global positioning system (GPS) to track individual birds for their welfare/health based on their distribution patterns.…”

Automatic detection of brown hens in cage-free houses with deep learning methods

“…The location loss is CIoU loss, and only the location loss of positive samples is calculated. The formula for calculating CIoU's loss is shown in Formula ( 8 ): where IoU is the intersection ratio, ρ represents the Euclidean distance between b and , the former is the center point of the prediction box, the latter is the center point of the real box, c is the diagonal distance between the minimum closure region of the prediction box and the real box, α is the weight parameter, and v is used to measure the consistency of the aspect ratio.…”

“…It is estimated that 37 billion poultry will be produced per year by 2050 ( Yitbarek, 2019 ), accordingly, farmers will need to increase the production efficiency continuously to meet the growing demand ( Rojas-Downing et al, 2017 ). Poultry and egg industry and researchers are dedicated to improving production efficiencies with limited natural resources, meanwhile, maintaining optimum animal welfare and health ( Chai et al, 2018 , 2019 ; Oliveira et al, 2019 ; Bist and Chai, 2022 ; Bist et al, 2023b ; Jacobs et al, 2023 ). In addition to production efficiency, animal welfare has been paid more attentions than ever before.…”