Brief Summary of Minutes of Annual Meeting

Objective 1. Energy/resource efficiency. This will include collaborative efforts on feed and fuel energy sources for poultry and facilities by geographical region, facility design, equipment efficiency, management, and modeling energy use in poultry systems. Ventilation Manipulations. IL conducted an experiment using commercial male broilers. For the purpose of examining varying levels of constant atmospheric CO2 levels on broiler performance, the levels of 2,000, 4,000 and 8,000 ppm were used. In this experiment, ninety Ross 708 commercial broilers at 1 day of age were housed in each of the 3 chambers. This gave a final bird density of 0.65 ft2/bird up to 4 wk of age taking into account feeder and waterer space. The experimental period was from Day 1 to 4 wk of age. From Day 1 to 7 the lighting regime consisted of 23 hr light:1 hr dark at a light intensity of 3.25 foot candles (35 lux) at bird level. From Day 8 to 28 the lighting regime consisted of 20 hr light: 4 hr dark at a light intensity of 1 foot candle (10 lux) at bird level. The reduction in light intensity was accomplished by lowering the wattage of bulbs used. All chambers had the following temperature regimen. The target temperature was 30°, 27°, 24°, 22°, and 20°C at 1, 7, 14, 21, and 28 days of age, respectively. Prior to housing the birds, approximately 4 inches of ground corn cobs were placed in each chamber. The feeding and watering system consisted of two tube-type feeders and two plasson waterers. These feeders and waterers allowed for a feeder space of 0.75 in2/bird and ample water space per bird. From Day 1 to 28, all birds were fed ad libitum a regular broiler starter and grower diet. During the 4-wk trial mortality was very low and birds that died was not a result of the CO2 levels. This study revealed that constant exposure of 8000 ppm of CO2 did not have a damaging effect on broiler growth, feed intake or feed conversion. It was anticipated that exposing broilers to a constant level of high atmospheric CO2 would produce stunted body weight gain, reduced feed intake, and poor feed conversion. Total body weight gain was the lowest for birds subjected to 4000 ppm CO2, followed by 8000, then 2000 ppm CO2. During the first week birds exposed to the highest CO2 level gained the least, but they gained as much weight as birds exposed to the lowest CO2 level during Week 2. During Week 1, birds exposed to 8000 ppm CO2 ate the least; but during Week 2, these birds had the highest feed intake. Total feed intake was the greatest for birds exposed to the lowest level of CO2 (2000 ppm), followed by birds exposed to 8000 ppm, then 4000 ppm CO2. For feed conversion, there might have been an effect of atmospheric CO2 during week 2, with the lowest conversion being noted for the 8000 ppm CO2 environment. However, total average feed conversion was virtually the same for all CO2 treatments. In summary, these results indicate that exposing constant high atmospheric CO2 to growing broilers does not negatively affect body weight gain, feed intake, and feed conversion. Heat Stress Therapy. USDA-ARS, Purdue University, and University of Illinois conducted an experiment using cooled perches to reduce heat stress in laying hens. The provision of a cooled perch in which chilled water is circulated through a conventional galvanized pipe passing through the laying hen cage offers the potential for improved performance during both acute and chronic heat stress events, is amenable to both natural and mechanically ventilated systems, and provides a positive welfare aspect by providing birds with a means to express their natural perching behavior. Pullets, 16 wk of age, were assigned to 1 of 3 banks of 6 cages each. A bank consisted of 3 deck levels with 2 cages per deck. Each bank was assigned to 1 of 3 treatments from 16 to 32 wk of age: 1) conventional cages with round metal perches that circulated cooled water when perch temperature exceeded 25° C, 2) conventional cages with identical perches except there was no coolant, and 3) conventional cages with no perches. A 4 h acute heating episode where temperatures were increased to a range of 32.0 to 34.6° C was instigated when hens were 27 wk of age. Behavioral, production, physical, and physiological data were collected. Behavioral data were analyzed using the GLIMMIX procedure in SAS and focused on the proportions of hens perching, feeding and drinking, and the presence or absence of panting and wing spreading behaviors within each cage. Other data were subjected to an ANOVA or an analysis of covariance with BW as the covariate where appropriate using the MIXED model procedure of SAS. Through a summer pilot study in 2013, we demonstrated proof of concept that our engineering design for thermally cooling perches was effective in reducing hen core body temperature and delaying the onset of panting and wing spreading during an acute heating episode of 4 hours. Furthermore, once these stress related behaviors did become evident later in the hens with access to thermally cooled perches, they remained lower during and after the heating episode as compared to hens with access to perches that were not cooled and controls without perches (all P < 0.05). Thermally cooled perches reduced heterophil to lymphocyte ratio at both 27 (P < 0.01) and 32 (P < 0.05) wk of age; and lowed plasma total IgG concentrations at 32 wk of age (P < 0.05). However, thermally cooled perches used during a mild summer with 4 h of acute heat stress did not affect hen performance, expression of IL-1?, IL-6, TNF-?, iNOS, and TLR-4 mRNA or musculoskeletal health. This pilot study provides preliminary evidence that the cooled perch system may assist laying hens in coping with heat stress. Nutrition. CT conducted studies on aflatoxins in poultry feed. Aflatoxins (AF) are toxic metabolites mainly produced by molds, Aspergillus flavus and Aspergillus parasiticus. Contamination of poultry feed with AF is a major concern to the poultry industry due to serious economic losses stemming from poor performance, reduced egg production and diminished egg hatchability. Additonally, AF are the only mycotoxins regulated by the U.S. Food and Drug Administration (FDA) due to their carcinogenic and hepatotoxic effects, and their potential presence as residues in meat and eggs. We investigated the inhibitory effect of two GRAS, plant-derived compounds, namely carvacrol (CR) and trans-cinnamaldehyde (TC), on?A. flavus and A. parasiticus growth, and AF production during long-term storage in chicken feed. Two hundred gram portions of chicken feed supplemented with CR and TC (0%, 0.4%, 0.8%, and 1.0%) and inoculated with A. flavus (NRRL 3357) or A. parasiticus (NRRL 2999 or NRRL 4123) were stored at 25oC for 3 months. The mold population and AF concentrations in the feed were determined at 0, 1, 2, 3, 4, 8, and 12 weeks of storage. All studies were replicated three times with duplicate samples of each treatment. Carvacrol and TC substantially inhibited A. flavus and A. parasiticus growth and AF production in chicken feed during the entire storage period (P < 0.05). All the concentrations of CR and TC decreased AF concentrations in the feed to levels below the FDA regulated limit (20 ppb). However, feed samples with no added CR or TC yielded more than 40 ppb (NRRL 2999) and 30 ppb (NRRL 4123 and NRRL 3357) of AF. The results suggest that CR and TC could potentially be used as feed additives to control AF contamination in poultry feed. Objective 2. Evaluating commercial poultry production systems. This will include collaborative efforts on the characterization of the performance of conventional, alternative, and organic poultry production systems relative to air and water quality, nutrient management, acoustic environment, and animal health and welfare. IN conducted work as part of the multi-disciplinary and multi-institutional project of Coalition for Sustainable Egg Supply (CSES). The CSES project involves three housing systems for egg production at the same research farm site in the Midwest, USA, namely, a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. The CC house – 141.4 m L × 26.6 m W × 6.1m H had a nominal capacity of 200,000 hens (6 hens in a cage at a stocking density of 516 cm2 hen-1); and the cages were arranged in ten rows, eight tiers per cage row, with a perforated aisle walkway at 4-tier height. The AV house – 154.2 m L × 21.3 m W × 3.0 m H and the EC house – 154.2 m L × 13.7 m W × 4.0 m H each had a nominal capacity of 50,000 hens. The AV house had six rows of aviary colonies, and the EC house had five rows of 4-tier enriched colonies containing perches, nestbox, and scratch pads (60 hens per colony at a stocking density of 748 cm2 hen-1). The overarching goal of the CSES project, as stated in the opening article of this series, was to comprehensively evaluate the three egg production systems from the standpoints of animal behavior and well-being, environmental impact, egg safety and quality, food affordability, and worker health. So that all the area-specific papers would not have to repeat a detailed description of the production systems and the management practices, this paper is written to provide such description and used as a common reference by the companion papers. IN conducted studies on comprehensively assessing conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern USA over two single-cycle production flocks. The housing systems studied include a conventional cage (CC) house (200,000 hen capacity), an aviary (AV) house (50,000 hen capacity), and an enriched colony (EC) house (50,000 hen capacity). As an integral part of the CSES project, continual environmental monitoring over a 27-month period described in this paper quantifies indoor gaseous and particulate matter (PM) concentrations, thermal environment, and building ventilation rate (VR) of each house. Results show that similar indoor thermal environment in all three houses was maintained through ventilation management and environmental control. Gaseous and PM concentrations of the EC house were comparable with those of the CC house. In comparison, the AV house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher NH3 levels) and hens’ activities (higher PM levels) on it. Specifically, daily mean indoor ammonia (NH3) concentrations had the 95% confidence interval (C.I.) values of 3.8-4.2 (overall mean of 4.0) ppm for the CC house; 6.2-7.2 (overall mean of 6.7) ppm for the AV house; and 2.7-3.0 (overall mean of 2.8) ppm for the EC house. The 95% C.I. (overall mean) values of daily mean indoor carbon dioxide (CO2) concentrations were 1997-2170 (2083) ppm for the CC house, 2367-2582 (2475) ppm for the AV house, and 2124-2309 (2216) ppm for the EC house. Daily mean indoor methane (CH4) concentrations were similar for all three houses, with 95% C.I. values of 11.1-11.9 (overall mean of 11.5) ppm. The 95% C.I. values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg m-3, were, respectively, 0.57-0.61 (0.59) and 0.033-0.037 (0.035) for the CC house, 3.61-4.29 (3.95) and 0.374-0.446 (0.410) for the AV house, and 0.42-0.46 (0.44) and 0.054-0.059 (0.056) for the EC house. Investigation of mitigation practices to improve indoor air quality of the litter-floor AV housing system is warranted. As an integral part of the Coalition for Sustainable Egg Supply (CSES) Project, IN simultaneously monitored air emissions of three commercially-operated egg production systems at the house level and associated manure storage over two single-cycle flocks (18-78 weeks of age). The three housing systems were a) a conventional cage house (CC) with a 200,000-hen capacity (6 hens in a cage at a stocking density of 516 cm2 hen-1), b) an enriched colony house (EC) with a 50,000-hen capacity (60 hens per colony at a stocking density of 748 cm2 hen-1), and c) an aviary house (AV) with a 50,000-hen capacity (at a stocking density of 929 cm2 hen-1). The three hen houses were located on the same farm and were populated with Lohmann white hens of the same age. Indoor environment and house-level gaseous (ammonia – NH3, greenhouse gasses – GHG including carbon dioxide – CO2, methane – CH4 and nitrous oxide – N2O) and particulate matter (PM10, PM2.5) emissions were monitored continually. Gaseous emissions from the respective manure storage of each housing system were also monitored. Emission rates (ERs) are expressed as emission quantities per hen, per animal unit (AU, 500 kg live body weight), and per kg of egg output. House-level NH3 ER (g hen-1 d-1) of EC (0.054) was significantly lower than that of CC (0.082) or AV (0.112) (P<0.05). House-level CO2 ER (g hen-1 d-1) was lower for CC (68.4) than for EC and AV (74.0-74.4), and CH4 ER (g hen-1 d-1) was similar for all three houses (0.07–0.08). House-level PM ER (mg hen-1 d-1), essentially representing the farm-level PM ER, was significantly higher for AV (PM10 of 100.3 and PM2.5 of 8.8) as compared to CC (PM10 of 15.7 and PM2.5 of 0.9) or EC (PM10 of 15.6 and PM2.5 of 1.7) (P<0.05). The farm-level (house plus manure storage) NH3 ER (g hen-1d-1) was significantly lower for the EC system (0.16) as compared to the CC (0.29) or AV (0.30) system (P<0.05). As expected, the magnitudes of GHG emissions were rather small for all three production systems. Data from this study enable comparative assessment of conventional vs. alternative hen-housing systems regarding air emissions and enhance the U.S. national air emissions inventory for farm animal operations. NC estimated the costs and benefits of implementing the proposed rule for laying hens, compared with alternatives. For the regulatory proposals under Option 2 the regulatory cost will be zero as most of producers are already in compliance with the proposed regulation. The anticipated benefits of this regulation will be zero as well because the current market prices already reflect the consumers’ willingness to pay for the existing animal welfare conditions. For the regulatory proposals under Option 3, prior to market adjustments, the average regulatory burden for the entire organic egg industry will amount to $0.09 per dozen eggs, with extreme variations between $0 for small operations and $2.30 per dozen for large operations. If we rely on the average price of organic eggs of $2.69 per dozen and assume the maximum estimated benefits associated with improved animal welfare conditions that consumers would be willing to pay of about 30% above the current market price, the estimated benefits of regulation amount to $0.81 per dozen eggs. Based on the findings we conclude that Option 2 is welfare neutral and could be easily adopted as it is already adopted by representative producers. For Option 3, the benefit-cost ratio is larger than 1 which indicates that the proposal passes the benefit-cost ratio test. The obtained result, however, has to be interpreted with serious reservation because of the differential impact that the proposed regulation would have on different industry participants. Under Option 3, the impact of the proposed changes on small organic egg producers is negligible because most small producers are operating under conditions similar to the proposed living standards. However, costs will increase substantially for large organic egg producers and likely cause a substantial number of producers to exit organic production and switch to conventional production which would cause a substantial decline in the prices of conventional eggs and organic feed in the short run. Objective 3. Establishing parameters influenced by the production system and strains utilized within the poultry industry. This collaborative research will encompass the areas of poultry nutrition, physiology, behavior, well-being, food safety and quality, and economic evaluation of poultry production systems. Poultry and disease control. CT conducted work on reducing egg-borne transmission of Salmonella enteritidis in laying hens. One hundred twenty Single Comb White Leghorn hens were randomly assigned to 6 treatments (n = 20/treatment): a negative control (?ve SE, ?ve CA), 2 compound controls (?ve SE, +ve 0.75% or 1% vol/wt CA), a positive control (+ve SE, ?ve CA), a low dose treatment (+ve SE, +ve 0.75% CA) and a high dose treatment (+ve SE, +ve 1% CA). On d 0, birds were tested for any inherent Salmonella (n = 5/experiment), and CA was supplemented in the feed at the aforementioned levels for 64 d. On d 10, birds in the positive controls and low dose and high dose treatments were challenged with a 5-strain mixture of SE (10 log10 cfu/bird) by crop gavage. After 4 d of challenge, eggs were collected and examined for SE in the yolk and on the shell daily until the end of the trial. On d 64, 10 birds from each treatment were killed to determine SE presence in the cecum, liver, and oviduct. Caprylic acid at 0.75% reduced SE on shell by ~21% and in yolk by 24%, whereas supplementation of 1% CA reduced SE by ~44% on shell and ~32% in yolk. Additionally, CA at both concentrations reduced SE in cecum, liver and oviduct (P < 0.05) by ~30 to 40% compared with control birds. No significant differences in egg production were observed among the different treatment groups (P> 0.05). The results suggest that CA could potentially be used as a feed additive to reduce egg-borne transmission of SE in layer chickens. In another study, CT examined methods to reduce SE colonization in broiler chickens. Two naturally occurring, generally recognized as safe compounds, namely ?- resorcylic acid (BR), (0.5%, 1%) chitosan (CH) (0.5%, 1%), and their combination (BR -1% and CH -1%; BR – 0.5% and CH-0.5%) were investigated for reducing Salmonella Enteritidis (SE) colonization in broiler chickens. One hundred sixty, day-old chicks were randomly allocated to eight treatments (n=20): (1) a negative control (no SE challenge or supplemented compound), (2) a CH control (no SE, but 0.5 or 1% CH), (3) a BR control (no SE, but 0.5 or 1% BR), (4) a CH and BR combination control (no SE, but 0.5 or 1% CH and 0.5 or 1% BR), (5) a positive control (SE challenge, but no CH or BR) (6) CH treatment (SE and 0.5 or 1% CH), (7) BR treatment (SE and 0.5 or 1% BR) and (8) a CH and BR combination treatment (SE and CH and BR at 0.5 or 1%). CH and BR were supplemented in the feed for 20 days, starting on day 0. On day 8, birds in the positive control, CH and BR treatments were challenged with SE (8 log10 CFU/bird) by crop gavage. After 10 days of challenge, 10 birds per treatment (n=10) were sacrificed by CO2 asphyxiation, and cecum, liver and crop from each bird were collected for SE enumeration. The SE counts recovered from the cecal samples of the control birds ranged from 4 to 5 log10 CFU/g after 10 days post infection. CH at 1% reduced cecal SE by ~ 2 log10 CFU/g, whereas BR (1%) reduced SE by ~ 3 log10 CFU/g. The combination treatment containing BR and CH at 0.5 or 1% was effective in reducing cecal SE by ~ 2 -2.5 log10 CFU/g. Similarly, BR (1%) and CH (1%) significantly decreased SE by ~ 2.5 and 1.5 log10 CFU/g, respectively and their combination decreased SE by ~1.5 log10 CFU/g in liver, when compared to controls. In the crop, CH (1%) and BR (1%) reduced SE by ~2.3 log10 CFU/g and by ~1.3 log 10 CFU/g, respectively. The cecal endogenous bacterial counts and pH did not differ (P > 0.05) among the various treatments. Although supplementation of CH and BR at 0.05% had no effect on the body weight of birds (P > 0.05), the treatments containing 1% BR or CH slightly decreased the body weight (P < 0.05). IN conducted a study to determine minimum horizontal distance (HD) between perches for laying hens using qualitative and quantitative behavioral analysis. A real-time monitoring system was developed to record hen’s perching behaviors, such as the number of perching hens, perching duration, perching trips, and the pattern of perch occupancy. Three groups of sixteen W-36 laying hens (68 weeks old at test onset) with prior perching experience were used. For each group, hens were kept in an enriched wire-mesh floor pen (1.2 × 1.2 × 1.2m) equipped with two parallel perches (15 cm perch space/hen). The HD between the perches were varied sequentially at 60, 40, 30, 25, 20, and 15 cm; then varied again in a reversed order. The minimum HD that led to no significant change in hen’s perching behavior was determined. Results showed that reduction of HD to 25 cm did not significantly restrain hen’s perching behavior; however, HD <25 cm significantly reduced the proportion of perching hens. When HD was insufficient, more perching trips occurred during the 45 min prior to dark period, indicating increase in perching competition. Meanwhile, hens perched interlacing with one another and tended to perch outwards from the opposite perches or hens during dark period, which might be a strategy to use the perch more efficiently. Horizontal distance of 60 cm increased the perching duration and reduced the perching trips during light period; however these two behavioral responses were not affected by HD <60 cm. Therefore, 25 cm is suggested as the minimum HD between laying-hen perches, 30 cm being preferable, and large HD’s such as 60 cm being ecessive. IN conducted a bird behavior study. Housing design and management schemes (e.g., bird stocking density) in egg production can impact hens’ ability to perform natural behaviors and production economic efficiency. It is therefore of socio-economic importance to quantify the effects of such schemes on laying-hen behaviors, which may in turn have implications on the animals’ well-being. Video recording and manual video analysis is the most common approach used to track and register laying-hen behaviors. However, such manual video analyses are labor intensive and are prone to human error, and the number of target objects that can be tracked simultaneously is small. In this study, we developed a novel method for automated quantification of certain behaviors of individual laying hens in a group-housed setting (1.2 m x 1.2 m pen), such as locomotion, perching, feeding, drinking, and nesting. Image processing techniques were employed on top-view images captured with a state-of-the-art time-of-flight (ToF) of light based 3D vision camera for identification as well as tracking of individual birds in the group with support from a passive radio-frequency identification (RFID) system. Each hen was tagged with a unique RFID transponder attached to the lower part of her leg. An RFID sensor grid consisting of 20 antennas installed underneath the pen floor was used as a recovery system in situations where the imaging system failed to maintain identities of the birds. Spatial as well as temporal data were used to extract the aforementioned behaviors of each bird. To test the performance of the tracking system, we examined the effects of two stocking densities (2880 vs. 1440 cm2 hen-1) and two perching spaces (24.4 vs. 12.2 cm of perch per hen) on bird behaviors, corresponding to five hens vs. ten hens, respectively, in the 1.2 m x 1.2 m pen. The system was able to discern the impact of the physical environment (space allocation) on behaviors of the birds, with a 95% agreement in tracking the movement trajectories of the hens between the automated measurement and human labeling. This system enables researchers to more effectively assess the impact of housing and/or management factors or health status on bird behaviors. In this project, NC estimate the costs and benefits of implementing the proposed rule for changes in living conditions for organic broilers. In contrast to the effects of the proposed rule for changes in living conditions for laying hens, the effects of the rule on organic broilers is anticipated to be relatively limited. All producers are already in compliance with Option 2 of the rule, and changes required under Option 3 are minimal for most producers. Using the per-farm estimated regulatory costs and the estimates of production volumes and actual prices, the total estimated annual industry cost under Option 3 is $2.4 million, which represents 0.1% of total industry revenue. The estimated benefits associated with this type of perceived animal welfare improvement are high enough to cover the anticipated cost, and the proposed option easily passes the benefit-cost ratio test.

CT Upadhyaya, I., A Upadhyay, A. Kollanoor-Johny, M.J. Darre and K. Venkitanarayanan. 2013 Effect of Plant Derived Antimicrobials on Salmonella Enteritidis Adhesion to and Invasion of Primary Chicken Oviduct Epithelial Cells in vitro and Virulence Gene Expression Int. J. Mol. Sci. 14(5), 10608-10625 Upadhyaya, I., A. Upadhyay, H.-B.Yin, Z. Droczdowich, M. Nair, V. K. Bhattaram, D. P. Karumathil, S. Mooyottu,, M. I. Khan, D. Schreiber, A. Kollanoor-Johny, M. J. Darre, K. Venkitanarayanan. 2014. Reducing egg-borne transmission of Salmonella Enteritidis in layer chickens by in-feed supplementation of caprylic acid. Poult.Sci. 93(E-Suppl. 1):32. H.Yin, A. Kollanoor-Johny; M.J. Darre; K. Venkitanarayanan. 2014. Effect of carvacrol and trans-cinnamaldehyde on Aspergillus flavus and Aspergillus parasiticus growth and aflatoxin production in poultry feed Poult. Sci. 93(E-Suppl. 1):17-18. I. Upadhyaya, A. Upadhyay, H. Yin, Meera Nair, D. Karumathil, V. Bhattaram, Jianping Li, M. Khan, A. Kollanoor-Johny, M. J. Darre, A. Donoghue, D. Donoghue and K. Venkitanarayanan 2014. Effect of ? –resorcylic acid and Chitosan on reducing Salmonella Enteritidis colonization in 21-day-old broiler chicks Poult.Sci. 93(E-Suppl. 1):70. Darre, M. J.; A. Kollanoor-Johny; K. Venkitanarayanan; I. Upadhyaya 2014 Practical implications of plant-derived antimicrobials in poultry diets for the control of Salmonella Enteritidis. J. Appl. Poult. Res. 23:1-5. Upadhyaya, I, A. Kollanoor-Johny; M. J. Darre; K. Venkitanarayanan. 2014. Efficacy of plant-derived antimicrobials for reducing egg-borne transmission of Salmonella Enteritidis. J. Appl. Poult. Res. 23:1-10. IL Koelkebeck, K.W., S. dePersio, K. Lima, P.C. Harrison, C. Utterback, P. Utterback, R.N. Dilger, R.S. Gates, A. Green, and J.M. Campbell. 2014. Evaluation of feeding spray-dried bovine plasma protein on production performance of laying hens exposed to high ambient temperatures. J. Appl. Poult. Res. 23:393-402. Bland, K., P. Utterback, K. Koelkebeck, and C. Parsons. 2014. Evaluation of feeding various sources of distillers dried grains with solubles in non-feed-withdrawal molt programs for laying hens. Poult. Sci. 93:1421-1427. dePersio, S., P.L. Utterback, C.W. Utterback, S. Rochell, N.O. Sullivan, K. Bregendahl, J. Arango, C.M. Parsons, and K.W. Koelkebeck. 2014. Effects of feeding diets varying in energy and nutrient density to Hy-Line W-36 laying hens on production performance and economics. Poult. Sci. 93:(submitted). IN Liedtke, E. A., P. Y. Hester, G. Vezzoli, R. S. Gates, S. A. Enneking, H. W. Cheng, and M. M. Makagon. 2014. The effects of chilled perches on body surface temperature of laying hens exposed to an acute heat episode. Proc. 12th ISAE North-American Regional Meeting, page 50. Cheng, H.W., M. M. Makagon, R. S. Gates, J. Y. Hu, S. A. Enneking, and P. Y. Hester. 2014. The effect of thermally cooled perches installed in cages on White Leghorn hen performance. Poultry Sci. 93 (E-Suppl.1):92. Hester, P. Y., M. M. Makagon, R. S. Gates, J. Y. Hu, S. A. Enneking, and H.W. Cheng. 2014. The musculoskeletal health of caged White Leghorn hens with access to thermally cooled perches. Poultry Sci. 93 (E-Suppl.1):93. Makagon, M. M., P. Y. Hester, G. Vezzoli, R. S. Gates, S. A. Enneking, and H. W. Cheng. 2014. Access to cooling perches affects the behavioral responses of laying hens during acute heat stress. Proc. 48th Congress of the International Society for Applied Ethology (Estevez, I., Manteca, X., Martin, R.H. and Averos, X., eds.). Wageningen Academic Publishers, The Netherlands, page 181. Gates, R.S., S.A. Enneking, Y. Xiong, P.Y. Hester, J.M. Makagon and H.W. Cheng. 2014. Design and performance of cooled perches for alternative egg laying production systems. Paper No. 141901235. ASABE and CSBE/SCGAB Annual International Meeting, Montreal. 13-16 July. St. Joseph, MI: ASABE. IA Akarmi, A., L. Tang, and H. Xin. 2014. Automated tracking and behavior quantification of laying hens using 3D computer vision and radio frequency identification technologies. Transactions of the ASABE 57(5): 1455-1472. Hayes, M.D. H. Xin, H. Li, T. A. Shepherd, and J. P. Stinn. 2014. Electricity and fuel usage of aviary layer houses in the Midwestern USA. Applied Engineering in Agriculture 30(2): 259-266. Kang, J., T. Wang, H. Xin, and Z. Wen. 2014. A laboratory study of mitigating ammonia gas emission from animal production operations using microalgae. J. Air and Waste Management Association 64(3): 330-339. Karcher, D.M., D.R. Jones, Z. Abdo, Y. Zhao, T.A. Shepherd, and H. Xin. 2014. Impact of commercial housing system and nutrition and energy intake on laying hen performance and egg quality parameters. Poultry Science (accepted for publication). Liu, K, H. Xin, T. A. Shepherd, and Y. Zhao. 2014. Determination of minimum horizontal distance between laying-hen perches. Technical Paper No. 1901652, presented at the 2014 ASABE and CSBE/SCGAB Annual International Meeting Sponsored by ASABE, Montreal, Quebec Canada, July 13 – 16, 2014. St. Joseph, MI: ASABE Mendes, L.B., H. Xin, J.W. Nascimento, and H. Li. 2014. Evaluation of a soil moisture sensor for real-time measurement of poultry manure or litter moisture content. Applied Engineering in Agriculture 30(2): 277-284. Pelletier, N., M. Ibarburu, and H. Xin. 2014. Comparative assessment of the environmental footprint of the U.S. egg industry in 1960 and 2010. Poultry Science 93:241-255 Shepherd, T.A., Y. Zhao, H. Li, J.P. Stinn, M.D. Hayes, and H. Xin. 2014. Environmental assessment of three laying-hen housing systems– Part II: ammonia, greenhouse gas, and particulate matter emissions. Poultry Science (accepted for publication). Wang, Y., H. Dong, Z. Zhu, C. Liu, and H. Xin. 2014. Comparison of greenhouse gas and ammonia emissions during storage of raw liquid pig manure and biogas digester effluent. Transactions of the ASABE 57(2):635-645. Wang, Y., H. Dong, Z. Zhu, T. Li, K. Mei, and H. Xin. 2014. Ammonia and greenhouse gas emissions from biogas digester effluent stored at different depths. Transactions of the ASABE 57(5): 1483-1491. Zhao, Y., A. Aarnink, and H. Xin. 2014. Inactivation of airborne Enterococcus faecalis and infectious bursal disease virus using a pilot-scale ultraviolet photocatalytic oxidation scrubber. Journal of the Air & Waste Management Association 64(1):38-46. Zhao, Y, H. Xin, D. Zhao, W. Zheng, W. Tian, H. Ma, K. Liu, H. Hu, T. Wang, M.L. Soupir. 2014. Free chlorine loss during spray of membrane-less acidic electrolyzed water and its antimicrobial effect on airborne bacteria from poultry house. Annals of Agricultural and Environmental Medicine 21(2):249-255. Zhao, Y., T. A. Shepherd, J. Swanson, J. A. Mench, D.M. Karcher, and H. Xin. 2014. Comparative evaluation of three laying-hen housing systems: description of the production systems and management practices. Poultry Science (accepted) Zhao, Y., T.A. Shepherd, T.A., H. Li, J.P. Stinn, M.D. Hayes, and H. Xin. 2014. Environmental assessment of three laying-hen housing systems–Part I: ammonia, greenhouse gas, and particulate matter emissions. Poultry Science (accepted) Zheng, W., Y. Zhao, H. Xin, B. Li, R.S. Gates, Y. Zhang and M.L. Soupir. 2014. Airborne particulate matter and bacteria reduction from spraying slightly acidic electrolyzed water in an experimental aviary laying-hen housing system. Transactions of the ASABE 57(1):229-236. Zhu, Z., H. Dong, J. Xi, and H. Xin. 2014. Ammonia and greenhouse gas emissions from co-composting of dead hens with manure as affected by forced aeration rate. Transactions of the ASABE 57(1):211-217. NC Vukina, T., K. E. Anderson, and M. K. Muth. 2014. 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