Particulate Matter Suppression and Heat Stress Relief in a Cage-free Hen House

Transcription

1 Agricultural and Biosystems Engineering Conference Proceedings and Presentations Agricultural and Biosystems Engineering 2018 Particulate Matter Suppression and Heat Stress Relief in a Cage-free Hen House Lilong Chai University of Georgia Hongwei Xin Iowa State University, hxin@iastate.edu Yu Wang Iowa State University, yuw@iastate.edu Jofran Oliveira Iowa State University, jofran@iastate.edu Kailao Wang Iowa State University See Follow next page this for and additional additional authors works at: Part of the Agriculture Commons, Bioresource and Agricultural Engineering Commons, Environmental Health Commons, and the Poultry or Avian Science Commons The complete bibliographic information for this item can be found at abe_eng_conf/571. For information on how to cite this item, please visit howtocite.html. This Presentation is brought to you for free and open access by the Agricultural and Biosystems Engineering at Iowa State University Digital Repository. It has been accepted for inclusion in Agricultural and Biosystems Engineering Conference Proceedings and Presentations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact digirep@iastate.edu.

2 Particulate Matter Suppression and Heat Stress Relief in a Cage-free Hen House Abstract Compared to conventional cage production system, 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 many inherent environmental challenges, among which are high levels of particulate matter (PM). Spraying liquid agent (e.g., 125 ml m-2 per cm litter depth) has been shown to effectively mitigate the generation of PM by 60%-70% from CF henhouse litter in our previous lab-scale tests. The objectives of this study were to verify the lab-study findings of PM reduction with liquid spray on a commercial CF farm and to evaluate the cooling effect of liquid spray on hens in hot weather. This study was conducted with a commercial aviary CF house (50,000 laying hens) in Iowa during winter of and summer of A water sprinkling system was installed in half of the experimental henhouse in the length direction (treatment section), whereas the other half of the henhouse served as the control. Results show that the PM emission was reduced by 37%-51%. Adjusting spray dosage according to litter depth is necessary for maintaining a certain reduction efficiency. Litter moisture content of the treatment sections was 9%-14% higher relative to the control, but NH3 concentrations in treatment and control were similar. For the summer cooling, sprinkled hens had up to 7 oc lower body surface temperature than non-sprinkled one immediately after a 20-sec or 30 ml m-2 water spray. The sprinkled hens were still 5 oc cooler than the non-sprinkled ones 3 min after spray. The cooling effect for some birds lasted for about 10 min, but most would dry out soon under the testing conditions (temperature of 35 oc and relative humidity of 32%). Keywords Egg production, animal welfare, worker health, air quality, cooling Disciplines Agriculture Bioresource and Agricultural Engineering Environmental Health Poultry or Avian Science Comments This presentation is published as Chai, Lilong, Hongwei Xin, Jofran Oliveira, Yu Wang, Kailao Wang, and Yang Zhao. "Particulate Matter Suppression and Heat Stress Relief in a Cage-free Hen House." 10th International Livestock Environment Symposium (ILES X). Omaha, NE. September 25-27, Paper No. ILES DOI: /iles Posted with permission. Authors Lilong Chai, Hongwei Xin, Yu Wang, Jofran Oliveira, Kailao Wang, and Yang Zhao This presentation is available at Iowa State University Digital Repository:

3 An ASABE Meeting Presentation DOI: Paper Number: ILES Particulate Matter Suppression and Heat Stress Relief in a Cage-free Hen House Lilong Chai 1, Hongwei Xin 2 *, Yu Wang 2, Jofran Oliveira 2, Kailao Wang 2, Yang Zhao 3 1. Department of Poultry Science, University of Georgia, Athens, GA 30602, USA 2. Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011, USA 3. Department of Agricultural and Biological Engineering, Mississippi State University, MS 39762, USA * Corresponding author: (T), hxin@iastate.edu ( ) Written for presentation at the 10 th International Livestock Environment Symposium (ILES X) Sponsored by ASABE Omaha, Nebraska, USA September 25-27, 2018 ABSTRACT. Compared to conventional cage production system, 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 many inherent environmental challenges, among which are high levels of particulate matter (PM). Spraying liquid agent (e.g., 125 ml m -2 per cm litter depth) has been shown to effectively mitigate the generation of PM by 60%-70% from CF henhouse litter in our previous lab-scale tests. The objectives of this study were to verify the lab-study findings of PM reduction with liquid spray on a commercial CF farm and to evaluate the cooling effect of liquid spray on hens in hot weather. This study was conducted with a commercial aviary CF house (50,000 laying hens) in Iowa during winter of and summer of A water sprinkling system was installed in half of the experimental henhouse in the length direction (treatment section), whereas the other half of the henhouse served as the control. Results show that the PM emission was reduced by 37%-51%. Adjusting spray dosage according to litter depth is necessary for maintaining a certain reduction efficiency. Litter moisture content of the treatment sections was 9%-14% higher relative to the control, but NH 3 concentrations in treatment and control were similar. For the summer cooling, sprinkled hens had up to 7 o C lower body surface temperature than non-sprinkled one immediately after a 20-sec or 30 ml m -2 water spray. The sprinkled hens were still 5 o C cooler than the non-sprinkled ones 3 min after spray. The cooling effect for some birds lasted for about 10 min, but most would dry out soon under the testing conditions (temperature of 35 o C and relative humidity of 32%). Keywords: Egg production; animal welfare; worker health; air quality; cooling. Introduction Concerns over animal welfare have led to pledges of sourcing only cage-free (CF) eggs by many U.S. food retailers and restaurants. According to the current number of pledges, it would take more than 70% of the current US layer inventory to meet the pledged demand by 2025 (AEB, 2018). Compared to conventional cage system, cage-free (CF) hen housing offers The authors are solely responsible for the content of this meeting presentation. The presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Meeting presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications. Publish your paper in our journal after successfully completing the peer review process. See for details. Citation of this work should state that it is from an ASABE meeting paper. EXAMPLE: Author s Last Name, Initials Title of presentation. ASABE Paper No St. Joseph, MI.: ASABE. For information about securing permission to reprint or reproduce a meeting presentation, please contact ASABE at (2950 Niles Road, St. Joseph, MI USA). 10 th International Livestock Environment Symposium (ILES X) Page 3

4 hens more space and opportunities to exercise their natural behaviors (Xin, 2016). However, CF housing poses many environmental challenges, such as high particulate matter (PM) levels, especially during cold weather when the house has limited ventilation (Takai et al., 1998; Hayes et al., 2013; Zhao et al., 2013; Shepherd et al., 2015). It has been reported that PM 10 levels (~4 mg m -3 ) in aviary CF houses were 6-9 times higher than conventional cage manure-belt and enriched colony houses (Zhao et al., 2015). The PM 10 levels in CF henhouses are far higher than the 24 h concentration threshold of 150 μg m -3 set by U.S. EPA to protect public welfare (U.S. EPA, 2015). Higher levels of PM in CF house air can carry more airborne microorganisms and endotoxins which, once inhaled, may trigger respiratory diseases to animals and/or their caretakers (Cambra-López et al., 2010). Therefore, mitigating PM levels is imperative to protecting the health and well-being of the animals and the caretakers; and improving the environmental stewardship of CF egg farms (Xin et al., 2011; EPA, 2015). Spraying liquid agents onto litter floor, such as tap water, acidic water, electrolyzed water, and mixture of water and soybean or canola oil, has been shown to reduce dust level or disinfect poultry houses, because high PM levels in CF hen houses primarily stem from the hen activities on litter floor (Zheng et al., 2014; Adell et al., 2015; Winkel, et al., 2016; Chai et al., 2017, 2018b). Properly controlling the water spray amount could maintain over 50% PM reduction efficiency without causing NH 3 issue (Chai et al., 2018a). Besides air quality improvement, water spray can also alleviate heat stress in the hen house in hot summer when laying hens tend to have higher mortality and lower egg production efficiency (Chepete and Xin, 2000; Mashaly et al., 2004). Surface wetting has been proven effective to cool birds and reduce mortality in poultry (Chepete and Xin, 2000; Ikeguchi and Xin, 2001; Tao and Xin, 2003; Liang et al., 2014). Most of previous hen cooling studies were for conventional cage system or broiler production. There is a need for aviary CF systems because of the different system design and birds distribution. The objectives of this study were (1) to suppress PM level in a commercial aviary CF henhouse by spraying water at the specific dosage identified during prior lab test; and (2) to evaluate the potential cooling effect of water spray on CF hens in hot summer as measured by surface temperature reduction. Sprinkling system in cage-free (CF) henhouse Materials and Methods A commercial sprinkling system (Weeden Environments Inc., Ontario, Canada) was installed in a commercial aviary CF henhouse (50,000 hens-dekalb White, 155 L 21 W 3 H m) in central Iowa. Half of the house in the length direction (treatment) (fig.1), and the other half of the house (without spray) served as the control. The CF house had four rows of litter floor in the width direction (denoted as R1-R4, fig. 2). The two outside rows (R1 and R4) each had 1.2 m wide open litter and the two middle rows (R2 and R3) each had 2.8 m wide open litter. Each row was further divided into 10 sections (S1- S10) in the length direction by metal wire mesh with pass-through doors; hence totally there were 40 zones of litter floor (fig. 2). S1-S5 were treatment sections (highlighted in yellow) and S6-S10 were control sections. No sprinklers were installed for the litter area beneath the aviary structure system due to space limitation. Figure 1 The dust reduction sprinkling system (a) in a commercial aviary cage-free henhouse (b) For the different-width rows, different types of sprinklers were installed at 2.2 m above the litter floor. Twelve bow-tie sprinklers (each covering an area of 1.0 m 4.2 m) was installed for each of R1 and R4 (the narrow litter rows). For each of two middle (wider) rows (R2 and R3), 29 spiral sprinklers were installed (each covering an area of 6.15 m 2 ). All sprinkler lines had a water pressure of 276 kpa (40 psi). The sprinklers had a rated water output of 43 L hr -1 and 35 L hr -1 each for the 10 th International Livestock Environment Symposium (ILES X) Page 4

5 bow-tie and spiral types, respectively. Commercial litter additive (PLT) was prepared in case the liquid spray would cause high NH 3; but it was never used because the treatment section did not show significantly higher NH 3 than the control during the test. The farm tap water (ph=7.7) was sprayed during the test, although a tank and a pump was designed for this system (see fig. 1a) so that other types of liquid agents (e.g., electrolyzed water or slightly acidic electrolyzed water) may be sprayed as well in the future. Figure 2 Sprinkling (treatment) and control litter floor zones of the experimental commercial aviary cage-free henhouse (R-row, S-section; zones with red labels were monitored for environmental conditions). The water spray dosage of 125 ml m -2 corresponding to 1 cm litter depth had been shown to achieve over 60% PM reduction without causing NH 3 problem (Chai et al., 2018a) during the lab study that preceded this field verification test. This spray dosage was used as the base and adjusted according to the litter depth. The PM suppression test was conducted during winter of (October 2017 to Jan. 2018) when the CF house had higher PM levels due to reduced building ventilation. The tap water was sprayed at 62.5, 125, and 175 ml m -2 (i.e., 40, 80, and 115 sec for spiral sprinklers in middle rows and 22, 44, and 64 sec for bow-tie sprinklers in the narrow rows) during Trials 1, 2, and 3, respectively, once per day about 10 min before the hens access the litter floor (table 1). Table 1 Spray dosage for different litter depths Trial 1 Trial 2 Trial 3 Start time (first spray) 10/26/ /24/ /29/2017 Initial litter depth 0.5 cm 1 cm 1.4 cm Spray dosage 62.5 ml m ml m ml m -2 Spray time (spiral sprinkler-wider row) 40 sec 80 sec 115 sec Spray time (bow-tie sprinkler-narrow row) 22 sec 44 sec 64 sec Note: Each trial lasted for 28 d (14 d continuous spray, once-per-day, & 14 d dry period without spray). Enviromental factors monitoring An optical PM sensor (Dusttrak Drx Aerosol Monitor 8533, TSI Incorporated, Shoreview, MN) was used to measure PM concentrations of different particle sizes, i.e., PM 1, PM 2.5, PM 4, PM 10 and total suspended particulate (TSP), in 8 representatives spots of both treatment and control (fig. 3). Figure 3 PM monitoring in the aviary cage-free henhouse: (a) TSI monitor; (b) placement of the PM monitor at 0.35 m above floor (near the birds level). The TSI PM monitor was zero calibrated weekly and sent back for manufacturer calibration (multi points) twice during 10 th International Livestock Environment Symposium (ILES X) Page 5

6 the test (once immediately before the test and once in the middle of the test). Eight representative spots per control and treatment section (indicated in red labels in fig. 2) were monitored continuously for T/RH (HOBO MX2300, ONSET, Bourne, MA) and periodically for NH 3 and PM (monitored on d0, d1, d4, d7, d10, d13, d15, and d18 in each trial). The NH 3 concentrations were monitored with a portable NH 3 sensor (GasAlert, BW Technologies Ltd., Arlington, TX). Two locations (i.e., R3-S3 and R3-S8) were monitored for CO 2 (HOBO MAX Logger, ONSET, Bourne, MA). The CO 2 sensors and GasAlert NH 3 sensor were zero-span checked with standard calibration gases biweekly. Cooling test arrangement Cooling test was conducted in June 2018 when the CF house air temperature was higher than 30 o C by spraying water of 30 ml m -2 (20 sec for wider rows and 11 sec for narrow rows) between 15:00 h and 16:00 h when the CF hen house had the highest air temperature of the day. The body surface temperature of laying hens before, during and after the water spray was monitored with FLIR thermal cameras (FLIR T440, FLIR Systems Inc., Wilsonville, OR). Two newly manufacturercalibrated thermal cameras were used. One camera was for taking thermal images at 15 sec per frame and the other was taking video to monitor activities of birds. FLIR Tools/Tools+ program (FLIR Systems Inc., Wilsonville, OR) was used to analyze surface temperature of the hens. Results and Discussion Thermal environment and particulate matter (PM) reduction efficiency Air temperature (T) and RH of the control and treatment sections along with the outdoor during PM suppression test are shown in Figure 5. The indoor T was maintained relatively constant (20 o C-24 o C and RH of 55%-70%) through adjustment of the building ventilation rate (VR) and supplemental heating (liquid propone) as needed. The control and treatment sections had similar indoor T (fig. 4-a) and RH (fig. 4-b) during test (winter of ). Figure 4 Air temperature (a) and RH (b) during the test (T-T and T-C represents air temperature in treatment and control section; RH-T and RH-C represents air relative humidity in treatment and control section, respectively). Before spray (d0) of each trial, PM levels in the treatment and control were similar (fig. 5). After starting spray (d1-d14), the difference became clear, and the treatment had significantly lower PM levels (p<0.05). One day after stopping the spray (d15), there was still some difference between the two regimens; but the difference disappeared 3d after stopping the spray (d18). The PM of different sizes in the treatment was 37%-51% lower than in the control for the three trials. Higher spray dosages reduced dust level further, but not proportionally because the birds would mix the top and bottom of the litter during foraging and dust bathing. Therefore, adjusting spraying dosage according to litter depth is necessary. In addition, reduction efficiency in the field was lower than that in the lab test (60%-70%) because of less spray coverage. In the field, the water was just sprayed onto the open area of the litter floor. The litter area under the aviary structures did not receive spray due to limited space for installation of the sprinkling system. Another reason for not installing sprinklers under the system was the concern over the birds pecking on and damaging the sprinklers. 10 th International Livestock Environment Symposium (ILES X) Page 6

7 Figure 5 PM levels in treatment and control (monitored on d0, d1, d4, d7, d10, d13, d15, and d18 in each trial). The PM reduction efficiency of the current field study is close to but slightly lower than the reduction efficiency (i.e., 49%) reported by Zheng et al. (2014) with 80 ml m -2 water spray. But the efficiency is higher than the result (i.e., 18%) reported by Ogink et al. (2012) at 150 ml m -2 water spray for a CF hen house in the Netherlands and the result (i.e., 34%) reported by Zheng et al. (2012) at 216 ml m -2 for a layer breeding house in China. A number of reasons may have contributed to the difference in PM reduction at the similar spray dosage, such as spreader/sprinkler installation (e.g., coverage area and installation height), initial litter quality (e.g., LMC, litter depth and bedding materials), and flock management (e.g., lighting and feeding schedule, laying hen breed/age and activity level). A primary consideration in the current study is adjusting the spray dosage according to the litter depth. Heat stress relief of hens by water spray Figure 6 shows the hens in thermal images taken in section of R2-S2 before and after water spray at 30 ml m -2 (20 sec) at around 15:00h on 06/01/2018 when indoor air temperature was approximately 35 o C with a relative humidity of 32%. Figure 6 Thermal images of laying hen before and after water-spray cooling at 15:00 h on 6/1/2018: (a) 15 sec before spray; (b) during spray; (c) 15 sec after spray; (d) 3 min after spray. Before spray, hens body surface (back) were in red or bright color, corresponding to the high end of temperature in the IR thermograph scale (fig. 6-a). The bright area on hen s back reflects the area of no feather coverage. During or immediately after spray (fig. 6-b and fig. 6-c), the wetted birds were in green or blue color due to reduced body surface temperature. 10 th International Livestock Environment Symposium (ILES X) Page 7

8 Birds started to huddle in the area right under the sprinkler due to dripping water (fig.6-d). For assessing body surface temperature, 12 hens before spray (in fig. 6-a), 16 hens (8 dry and 8 wetted) 15 sec after spray (in fig. 6-c), and 14 hens (7 dry and 7 wetted) 3 min after the spray (in fig. 6-d) were analyzed with the FLIR tools. Dry hens body surface temperature in Figures 7-c and 7-d was 37.2 ± 0.2 o C (mean±sd, n=8) and 37.3 ± 0.3 o C (mean±sd, n=7), respectively, which is comparable to the hen body surface temperature of 37.2 ± 0.2 o C (mean±sd, n=12) before spray (fig. 6-a). The body surface (back) temperature (excluding the head and area without feather coverage on the back) of the wetted hens was 6 o C -7 o C lower than temperature of dry counterparts immediately (15 sec) after water spray (i.e., 37.1 o C for dry hens vs o C for wetted hens) (fig. 7). The body surface (back) temperature of wetted hens was still 5 o C cooler than the dry ones after 3 min. The cooling effect for some birds lasted up to 10 min, but most of them dried out within that duration according to thermal images or thermal videos. In addition, the water spray just covered the hens on litter floor but not the hens stayed in or beneath the system. Therefore, spraying water intermittently is necessary to reduce heat stress continuously and cover more hens, especially the ones from the system or beneath it. Caution should be taken to prevent hens from piling. Figure 7 Body surface (back) temperature: wetted hens vs. dry hens (a- 15 s after the spray; b- 3min after the spray). Dry hens were from the sprinkle-uncovered area either under the system or from the system. The indoor temperature and RH were not affected by the sprinkling operation, as shown in Figure 8. This is because the sprinkling system is different from conventional fogging cooling system in that the sprinkling system sprayed water at lower pressure (larger water droplets) onto the floor or hens body directly. In addition, the henhouse ventilation was at maximum during the cooling test; as such any extra moisture in the air and litter was quickly removed from the henhouse. Figure 9 shows the cooling effect of water spray on hens in CF house on 6/15/2018 when the outdoor and indoor air temperature was around 33 o C and 34.5 o C, respectively. According to thermal video, a laying hen was spotted staying on litter floor within the field of view (FOV) of two consecutive thermal images 15 sec before and after the water spray. The average hen back temperature (highlighted in black) was 37.4 o C and 30.7 o C before and after water spray, respectively. The body surface temperature was reduced by 6.7 o C, which agreed to the average cooling effect observed on 6/1/2018 (fig. 7). 10 th International Livestock Environment Symposium (ILES X) Page 8

9 Figure 8 Air temperature and RH in treatment and control sections of the aviary cage-free henhouse during cooling test on 06/01/2018 (T-T, treatment temperature, T-C, control temperature, RH-T, treatment RH, and RH-C, control RH). Figure 9 Thermal images of hens before and after water spray at 15:00 h on 6/15/2018: (a) 15 sec before spray, highlighted hen had body temperature of 37.4 o C; (b) 15 sec after the spray, highlighted hen had body surface temperature of 30.7 o C. Summary and Conclusions Spraying water at 125 ml m -2 per cm litter depth, once a day, reduced PM by 37%-51% as compared to no-spray in a commercial aviary cage-free henhouse during the winter of Higher spray dosages reduced dust level further, but reduction efficiency was not directly proportional to spray dosage because of mixing activities by the laying hens when foraging and/or dust-bathing on the litter. Adjusting spray dosage according to litter depth is necessary to maintain a certain reduction efficiency. Under the current spray scheme of once-a-day spray over 14 d, litter moisture content in the treatment was 9%-14% higher relative to the no-spray. Ammonia level was not affected by the water spray. Water spray at dosage of 30 ml m -2 has shown cooling effect of laying hens in the CF house when indoor air temperature was over 30 o C in that wetted hens had 6 o C -7 o C lower body surface temperature than dry hens immediately after the spray. The body surface temperature of wetted birds was still 5 o C lower than dry ones 3 min after the spray. Most hens would dry out in 8-10 min, but some were still wet over 10 min under the testing environmental conditions. Spraying water intermittently is necessary to reduce heat stress continuously and cover more hens. The cooling test is ongoing for identifying the best spray regimen and its potential effect on egg production and mortality. Acknowledgements The authors acknowledge the financial support of the USDA-NIFA Grant (Award No ) and the Egg Industry Center. We are also grateful to Iowa Cage Free, LLC, particularly Farm Manager Eckard Darrin and Assistant Manager Cody Lucero for providing the valuable assistance during the field test. 10 th International Livestock Environment Symposium (ILES X) Page 9

10 References American Egg Board (AEB) (visited on May 5th, 2018). Chai, L., Xin, H., Zhao, Y., Wang, T., Soupir, M. & Liu, K., 2018a. Mitigating ammonia and pm generations of cage-free henhouse litter with solid additive and liquid spray. Trans. ASABE., 61(1), Chai, L., Zhao, Y., Xin, H., Wang, T., Atilgan, A., Soupir, M. and Liu, K., Reduction of particulate matter and ammonia by spraying acidic electrolyzed water onto litter of aviary hen houses a lab-scale study. Trans. ASABE., 60(2), Chai, L., Zhao, Y., Xin, H., Wang, T., Soupir, M., 2018b. Mitigating airborne bacteria generations from cage-free layer litter by spraying acidic electrolysed water. Biosyst. Eng., 170, Chepete, H.J. and Xin, H., Cooling laying hens by intermittent partial surface sprinkling. Trans. ASAE., 43(4), Ikeguchi, A. and Xin, H Field evaluation of a sprinkling system for cooling commercial laying hens in Iowa. Appl. Eng Agric., 17(2): Liang, Y., Tabler, G.T., Costello, T.A., Berry, I.L., Watkins, S.E. and Thaxton, Y.V., Cooling broiler chickens by surface wetting: indoor thermal environment, water usage, and bird performance. Appl. Eng. Agric., 30(2), Mashaly, M. M., G. L. Hendricks 3rd, M. A. Kalama, A. E. Gehad, A. O. Abbas, and P. H. Patterson Effect of heat stress on production parameters and immune responses of commercial laying hens. Poult. Sci., 83(6), Ogink N.W.M., van Harn J, van Emous RA, Ellen HH., Top layer humidification of bedding material of laying hen houses to mitigate dust emissions: effects of water spraying on dust, ammonia and odor emissions. Proceedings of The Ninth International Livestock Environment Symposium; Jul Valencia, Spain; St. Joseph, MI, ASABE, Shepherd, T.A., Zhao, Y., Li, H., Stinn, J.P., Hayes, M.D. and Xin. H Environmental assessment of three laying-hen housing systems Part II: ammonia, greenhouse gas, and particulate matter emissions. Poult. Sci., 94(3), Takai, H., Pedersen, S., Johnsen, J.O., Metz, J.H.M., Koerkamp, P.G., Uenk, G.H., Phillips, V.R., Holden, M.R., Sneath, R.W., Short, J.L. and White, R.P Concentrations and emissions of airborne dust in livestock buildings in Northern Europe. J. Agric. Eng. Res., 70(1), Tao, X. and Xin, H., Surface wetting and its optimization to cool broiler chickens. Trans ASAE., 46(2): U.S. EPA National Ambient Air Quality Standards (NAAQS). (accessed on January 10th, 2018). Winkel, A., Van Riel, J. W., Van Emous, R. A., Aarnink, A. J. A., Koerkamp, P. G., & Ogink, N. W. M Abatement of particulate matter emission from experimental aviary housings for laying hens by spraying rapeseed oil. Poult. Sci., 95(12), Xin, H., Environmental challenges and opportunities with cage-free hen housing Systems. The XXV World s Poultry Congress, September 5-9, Beijing, China. Xin, H., Gates, R.S., Green, A.R., Mitloehner, F.M., Moore, Jr. P.A. and Wathes, C.M., Environmental impacts and sustainability of egg production systems. Poult. Sci., 90(1), Zhao, Y., Shepherd, T.A., Li, H., Stinn, J.P., Hayes, M.D., and Xin. H Environmental assessment of three laying-hen housing systems Part I: monitoring system and indoor air quality. Poult. Sci., 94(3), Zhao, Y, Xin, H., Shepherd, T.A., Hayes, M.D., Stinn, J.P. and H. Li Thermal environment, ammonia concentrations and ammonia emissions of aviary houses with white laying hens. Trans.ASABE, 56, (3): Zheng, W., Y. Zhao, H. Xin, B. Li, R.S. Gates, Y. Zhang and M.L. Soupir Airborne particulate matter and bacteria reduction from spraying slightly acidic electrolyzed water in an experimental aviary laying-hen housing system. Trans. ASABE., 57(1), th International Livestock Environment Symposium (ILES X) Page 10