Laying Hen Houses Research Articles

Air Quality Measurements in Laying Hens Housing

Abstract Ensuring good environmental conditions of the poultry houses can be costly for the farmers, but without it losses due to poor bird health and performance due to poor air quality can be much more detrimental to net returns. The goal of this study was to investigate the variations in air quality in various areas inside the laying hen houses. Ten houses with laying hen conventional battery cages were measured for O2, H2S, CO, NH3, temperature, relative humidity, CO2, airflow and luminance. The results of the physical measures showed that temperatures in the houses were between 15.31–25.6°C, the relative humidity 48.03-81.12%, while the luminance rarely exceeded 8 lux. As for the gasses, the values for NH3 rarely exceeded 8 ppm, although at some measuring points it reached 26 ppm. O2 was generally at 20.9 %, and the levels of CO2 were very low. No presence of H2S and CO was detected. In this study it was concluded that the measurement of the air quality in a house can vary depending of the places this measures are taken. Multiple measurement points are important because they may make the staff aware of the problems connected to low ventilation and culmination of harmful gases. The air quality in different positions in the houses is of great importance not only for the animal welfare, but also for the safety of the staff.

The Coalition for Sustainable Egg Supply: A unique public-private partnership for conducting research on the sustainability of animal housing systems using a multistakeholder approach.

The growing emphasis on ensuring the sustainability of animal agriculture is providing an impetus for the adoption of new approaches to structuring and conducting research. Sustainability is a complex topic involving many considerations related to the economic, social, and environmental impacts of production systems. Successfully addressing this topic requires multidisciplinary research as well as a high degree of communication with food system stakeholders to ensure that the research results contribute to informed decision making. In this paper, we provide an overview of a public-private partnership, the Coalition for Sustainable Egg Supply (CSES), which was formed to support research evaluating the sustainability of laying hen housing systems. Because of increasing public concerns about the behavioral restriction imposed on laying hens housed in conventional cages, the U.S. egg industry is faced with a need to transition to alternative systems. However, before the CSES project, there was limited information available about how this transition might affect trade-offs related to the sustainability of egg production. The goal of the CSES project was to provide this information by conducting holistic research on a commercial farm that had 3 different hen housing systems. The CSES members represented a variety of stakeholders, including food retailers and distributors, egg producers, universities, and governmental (USDA ARS) and nongovernmental organizations. The CSES was facilitated by a not-for-profit intermediary, the Center for Food Integrity, which was also responsible for communicating the research results to food system stakeholders, including via quantitative and qualitative consumer research. In this paper, we describe the structural aspects of the CSES that were responsible for the successful completion and dissemination of the research as well as the insights that were gained regarding multidisciplinary and multi-institutional collaboration, conducting commercial-scale research, fostering and maintaining stakeholder interaction, and communicating research results. Although not without limitations, this project demonstrates that public-private partnerships can be effective strategies for addressing sustainability questions related to animal agriculture and, thus, serves as a useful model for the other animal industries.

Incidence, Severity, and Welfare Implications of Lesions Observed Postmortem in Laying Hens from Commercial Noncage Farms in California and Iowa.

The egg industry is moving away from the use of conventional cages to enriched cage and noncage laying hen housing systems because of animal welfare concerns. In this study, the prevalence and severity of lesions in noncage laying hens from commercial farms in two of the largest egg-producing states, California and Iowa, were evaluated by postmortem examination. Hens that died or were culled were collected during early, mid, and late stages of the laying cycle from 16 houses on three farms. Of the 25 gross lesions identified for study, 22 were observed, with an average of four lesions per hen. Vent cannibalism, reduced feather cover, keel bone deformation, and beak abnormalities were the most frequent lesions, observed in ≥40% of hens. Other common lesions were cloacal prolapse (30.5%), footpad dermatitis (24.3%), and septicemia (23.1%). Beak abnormality and enteric disease had the highest proportion of severe lesions. Pearson chi-square analysis revealed a number of stage-of-lay effects (P ≤ 0.05), some of which differed by state. For both states combined, the lesions observed more frequently during early lay were beak abnormalities, northern fowl mite infestation, and cage layer fatigue, whereas during mid lay, they were poor feather cover, vent cannibalism, footpad dermatitis, keel bone deformation, respiratory disease and roundworms. Feather pecking and cloacal prolapse were most common during late lay. Although differences in hen genetics, farm management practices, and environmental factors could all have affected the results of this study, the information provides a better understanding of hen health in noncage housing systems and could help to identify potential interventions to reduce hen welfare problems.

Ammonia and greenhouse gas emissions from an enriched cage laying hen facility

Ammonia, methane, nitrous oxide and carbon dioxide emissions were measured during a complete production cycle in an enriched cage laying hen facility under Oceanic climate conditions. Continuous monitoring of gas concentration, ventilation rate and environmental parameters were conducted from April 2012 to September 2013. The seasonal and diurnal pattern of gas emissions was analysed. Seasonality effect was found for NH 3 emission, showing an average emission of 144.9 mg d −1 hen −1 and 90.3 mg d −1 hen −1 in summer and winter, respectively. On the contrary, diurnal pattern of NH 3 emission did not differ between these seasons. For CO 2 , mean emission values did not show seasonality, although the diurnal pattern differed between winter and summer. Results obtained for CH 4 and N 2 O emissions did not provide sufficient evidence to determine either seasonality or diurnal effect on these gases. An NH 3 emission factor of 7% of total N in manure was defined for this system. These losses increased at higher ventilation rates and lower belt cleaning frequencies. Thus, NH 3 mitigation strategies at housing level should consider both parameters. Further studies would be necessary to determine how these factors regulate NH 3 emission at laying hen houses.

Modeling of Dynamic Ammonia Concentrations in Two Commercial Layer Hen Houses

Ammonia (NH3) concentrations in confined layer hen houses are the highest among buildings of different animal species and are of great concern to indoor air quality and animal welfare. However, little has been done to investigate the dynamic relationships between NH3 concentrations and the influencing factors. A Distributed Lag Non-linear Model was applied to study the dynamics of NH3 in two high-rise layer houses using a two-year dataset, compiled with hourly data, and its two subsets of summer and winter. Three major influencing factors, the ventilation rate, outdoor temperature, and outdoor relative humidity, were identified to have lagged effects on indoor NH3 concentrations in both houses. The duration of lagged effects of ventilation rate ranged from non-observable (<1 h) to a few subsequent hours. However, in winter, the changes in ventilation rates within the low operational ranges were not sufficiently high to induce NH3 concentration changes. The effects of temperature were not observable in winter. Higher outdoor relative humidity was related to elevated NH3 concentrations in winter, with a lag time of about 1 h in both houses. The lagged effects were considerably different between summer and winter for all three influencing factors.

Nutrient flow and distribution in conventional cage, enriched colony, and aviary layer houses

This study was carried out to measure the mass flow and distribution of nutrients (N, C, S, P, and K) as well as solids and moisture in conventional cage (CC), enriched colony (EC), and aviary (AV) laying-hen houses with Lohmann LSL lite hens located on a commercial laying-hen farm in Iowa. The weight of consumed feed and water, and amounts of eggs and manure production were collected weekly from each house for 2 entire flocks for a total of 28 mo. Samples of feed, egg, manure, litter, and hens were regularly taken and analyzed for total solids and nutrients (N, C, S, P, and K). The nutrient losses to the atmosphere were calculated using a mass balance approach. The losses of nutrients were calculated by subtracting the nutrient contents in eggs, manure, and layer body weight gain from the nutrients intake. The research results showed that the feed intake and manure production rates were similar in the 3 houses. The average nutrient intake in feed, in g d−1 hen−1, for the 3 houses was 42.0 C, 2.96 N, 0.36 S, 0.55 P, and 0.79 K. The nutrient intake was partitioned as follow: C – 18% in eggs, 28% in manure, and 54% in air losses; N – 34% in eggs, 58% in manure, and 8% in air losses; S – 26% in eggs, 68% in manure, and 6% in air losses; P – 17% in eggs, 79% in manure, and 3.1% in air losses; and K – 9% in eggs, 89% in manure, and 1.6% in air losses. Manure removed from the EC house was drier than manure from the CC or AV house. Among the 3 hen houses studied, the EC house had the lowest nutrient losses and the AV house had the highest losses. Nutrient loss in CC was statistically similar to EC. But loss of N, C, and S in AV differed from CC and EC. Furthermore, the loss of P and K in the 3 housing systems was statistically similar. The AV had a doubled mortality rate compared to CC and EC.

Performance of an Infrared Photoacoustic Single Gas Analyzer in Measuring Ammonia from Poultry Houses

A single-gas photoacoustic analyzer, Chillgard RT, was evaluated for its performance of measuring ammonia (NH3) concentrations in poultry production under laboratory and field conditions, using a multi-gas photoacoustic analyzer, INNOVA 1412, as a reference method. Calibration gases were used to evaluate the cross-interferences of carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and water vapor on NH3 measurements by Chillgard RT. The response times of Chillgard RT and INNOVA were measured in the laboratory using four vessels containing broiler litter. Side-by-side field comparisons between the Chillgard RT and INNOVA were conducted on a laying-hen farm and a broiler farm over two five-month periods. A strong linear relationship existed between the Chillgard RT and INNOVA NH3 readings. The NH3 measurement by the Chillgard RT showed no effect by CO2, N2O, CH4, or water vapor under typical operational conditions in poultry operations. The Chillgard RT demonstrated a faster response to NH3 than the INNOVA. Following 120-s measurements, the Chillgard RT and INNOVA achieved 99.6% and 96.7% of the expected values, respectively, when the INNOVA was configured at a 30-s sampling interval. The INNOVA response time was positively affected by water vapor level in the air samples. The Chillgard RT overestimated NH3 concentrations by 3.24%, 10%, and 22.9% for laying-hen houses, stored boiler litter, and broiler houses, respectively, as compared to the INNOVA. Thus, performance of the Chillgard RT should be carefully validated before used in field NH3 measurements.

Comparison of Bioactive Compound Content in Egg Yolk Oil Extracted from Eggs Obtained from Different Laying Hen Housing Systems

Comparison of Bioactive Compound Content in Egg Yolk Oil Extracted from Eggs Obtained from Different Laying Hen Housing Systems

Impact of commercial housing systems and nutrient and energy intake on laying hen performance and egg quality parameters

The US egg industry is exploring alternative housing systems for laying hens. However, limited published research related to cage-free aviary systems and enriched colony cages exists related to production, egg quality, and hen nutrition. The laying hen's nutritional requirements and resulting productivity are well established with the conventional cage system, but diminutive research is available in regards to alternative housing systems. The restrictions exist with limited availability of alternative housing systems in research settings and the considerable expense for increased bird numbers in a replicate due to alternative housing system design. Therefore, the objective of the current study was to evaluate the impact of nutrient and energy intake on production and egg quality parameters from laying hens housed at a commercial facility. Lohmann LSL laying hens were housed in three systems: enriched colony cage, cage-free aviary, and conventional cage at a single commercial facility. Daily production records were collected along with dietary changes during 15 production periods (28-d each). Eggs were analyzed for shell strength, shell thickness, Haugh unit, vitelline membrane properties, and egg solids each period. An analysis of covariance (ANCOVA) coupled with a principal components analysis (PCA) approach was utilized to assess the impact of nutritional changes on production parameters and monitored egg quality factors. The traits of hen-day production and mortality had a response only in the PCA 2 direction. This finds that as house temperature and Met intake increases, there is an inflection point at which hen-day egg production is negatively effected. Dietary changes more directly influenced shell parameters, vitelline membrane parameters, and egg total solids as opposed to laying hen housing system. Therefore, further research needs to be conducted in controlled research settings on laying hen nutrient and energy intake in the alternative housing systems and resulting impact on egg quality measures.

Microbiological impact of three commercial laying hen housing systems

Hen housing for commercial egg production continues to be a societal and regulatory concern. Controlled studies have examined various aspects of egg safety, but a comprehensive assessment of commercial hen housing systems in the US has not been conducted. The current study is part of a holistic, multidisciplinary comparison of the diverse aspects of commercial conventional cage, enriched colony cage, and cage-free aviary housing systems and focuses on environmental and egg microbiology. Environmental swabs and eggshell pools were collected from all housing systems during 4 production periods. Total aerobes and coliforms were enumerated, and the prevalence of Salmonella and Campylobacter spp. was determined. Environmental aerobic and coliform counts were highest for aviary drag swabs (7.5 and 4.0 log cfu/mL, respectively) and enriched colony cage scratch pad swabs (6.8 and 3.8 log cfu/mL, respectively). Aviary floor and system wire shell pools had the greatest levels of aerobic contamination for all eggshell pools (4.9 and 4.1 log cfu/mL, respectively). Hens from all housing systems were shedding Salmonella spp. (89–100% of manure belt scraper blade swabs). The dry belt litter removal processes for all housing systems appear to affect Campylobacter spp. detection (0–41% of manure belt scraper blade swabs) considering detection of Campylobacter spp. was much higher for other environmental samples. Aviary forage area drag swabs were 100% contaminated with Campylobacter spp., whereas enriched colony cage scratch pads had a 93% positive rate. There were no differences in pathogen detection in the shell pools from the 3 housing systems. Results indicate egg safety is enhanced when hens in alternative housing systems use nest boxes. Additionally, current outcomes indicate the use of scratch pads in hen housing systems needs to be more thoroughly investigated for effects on hen health and egg safety.

Environmental assessment of three egg production systems–Part I: Monitoring system and indoor air quality

To comprehensively assess conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as the Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern United States over two single-cycle production flocks. The housing systems studied include a conventional cage house (200,000 hen capacity), an aviary house (50,000 hen capacity), and an enriched colony 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 concentrations, thermal environment, and building ventilation rate of each house. Results showed that similar indoor thermal environments in all three houses were maintained through ventilation management and environmental control. Gaseous and particulate matter concentrations of the enriched colony house were comparable with those of the conventional cage house. In comparison, the aviary house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher ammonia levels) and hens’ activities (higher particulate matter levels) in it. Specifically, daily mean indoor ammonia concentrations had the 95% confidence interval values of 3.8 to 4.2 (overall mean of 4.0) ppm for the conventional cage house; 6.2 to 7.2 (overall mean of 6.7) ppm for the aviary house; and 2.7 to 3.0 (overall mean of 2.8) ppm for the enriched colony house. The 95% confidence interval (overall mean) values of daily mean indoor carbon dioxide concentrations were 1997 to 2170 (2083) ppm for the conventional cage house, 2367 to 2582 (2475) ppm for the aviary house, and 2124 to 2309 (2216) ppm for the enriched colony house. Daily mean indoor methane concentrations were similar for all three houses, with 95% confidence interval values of 11.1 to 11.9 (overall mean of 11.5) ppm. The 95% confidence interval values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg/m3, were, respectively, 0.57 to 0.61 (0.59) and 0.033 to 0.037 (0.035) for the conventional cage house, 3.61 to 4.29 (3.95) and 0.374 to 0.446 (0.410) for the aviary house, and 0.42 to 0.46 (0.44) and 0.054 to 0.059 (0.056) for the enriched colony house. Investigation of mitigation practices to improve indoor air quality of the litter-floor aviary housing system is warranted.

Modification of aviary design reduces incidence of falls, collisions and keel bone damage in laying hens

Non-cage housing systems for laying hens such as aviaries provide greater freedom to perform species-specific behavior and thus are thought to improve welfare of the birds; however, aviaries are associated with a high prevalence of keel bone damage (fractures and deviations), which is a major welfare problem in commercial laying hens. Potential causes of keel bone damage are falls and collisions with internal housing structures that occur as birds move between tiers or perches in the aviary. The aim of this study was to investigate the scope for reducing keel bone damage by reducing falls and collisions through modifications of aviary design. Birds were kept in 20 pens in a laying hen house (225 hens per pen) that were assigned to four different treatments (n=5 pens per treatment group) including (1) control pens and pens modified by the addition of (2) perches, (3) platforms and (4) ramps. Video recordings at 19, 22, 29, 36 and 43 weeks of age were used to analyze controlled movements and falls (including details on occurrence of collision, cause of fall, height of fall and behavior after fall) during the transitional dusk and subsequent dark phase. Palpation assessments (focusing on fractures and deviations) using 20 focal hens per pen were conducted at 18, 20, 23, 30, 37, 44, 52 and 60 weeks of age. In comparison to the control group, we found 44% more controlled movements in the ramp (P=0.003) and 47% more controlled movements in the platform treatments (P=0.014) as well as 45% fewer falls (P=0.006) and 59% fewer collisions (P<0.001) in the ramp treatment. There were no significant differences between the control and perch treatments. Also, at 60 weeks of age, 23% fewer fractured keel bones were found in the ramp compared with the control treatment (P=0.0053). After slaughter at 66 weeks of age, no difference in keel bone damage was found between treatment groups and the prevalence of fractures increased to an average of 86%. As a potential mechanism to explain the differences in locomotion, we suggest that ramps facilitated movement in the vertical plane by providing a continuous path between the tiers and thus supported more natural behavior (i.e. walking and running) of the birds. As a consequence of reducing events that potentially damage keel bones, the installation of ramps may have reduced the prevalence of keel fractures for a major portion of the flock cycle. We conclude that aviary design and installation of specific internal housing structures (i.e. ramps and platforms) have considerable potential to reduce keel bone damage of laying hens in aviary systems.

Air disinfection in laying hen houses: Effect on airborne microorganisms with focus on Mycoplasma gallisepticum

The application of disinfectant thermo-nebulised into the air of laying hen houses to reduce airborne microorganisms was evaluated with emphasis on its effect on Mycoplasma gallisepticum. Two air disinfectant tests were conducted in two identical laying hen houses. One of the houses was used as the treatment, whereas the other was used as a control. Airborne microorganisms were sampled before, 1 h and 6 h after disinfection. Prior to disinfection, outdoor and indoor environmental conditions, temporal concentrations of particulate matter (PM10 and PM2.5), and the spatial distribution of airborne microorganisms were measured. The average pre-disinfection concentration for PM2.5 was 0.024 ± 0.025 mg m−3 and for PM10 was 0.546 ± 0.377 mg m−3, showing high proportions of particles from feathers and manure. The concentration of airborne mesophilic aerobic bacteria ranged from 4.1 to 5.7 log colony forming units, CFU m−3. No differences were obtained between sampling height and sampling in corridors. Under the test conditions, air disinfection using wide spectrum thermo-nebulised disinfectant was not effective in reducing the concentration of mesophilic aerobic bacteria, Enterobacteriaceae and M. gallisepticum in the air. Mycoplasma spp. was confirmed by qPCR on cage surfaces and chicken's feathers before and after disinfection. The presence of outdoor Mycoplasma spp. suggests that inlet air could be a source of entry of this pathogen. Further information on the relationship between PM and airborne microorganisms and their behaviour in the air are necessary to design adequate techniques to reduce them in livestock houses.

Evaluation of a dry filter and an electrostatic precipitator for exhaust air cleaning at commercial non-cage laying hen houses

The removal performance of two exhaust air cleaning systems for abatement of particulate matter (PM) emission in poultry houses were investigated: a commercially available dry filter (DF) and a full-scale prototype electrostatic precipitator (ESP). Each system was connected to two commercial, non-cage laying hen houses: one with aviary housing, the other with floor housing. At each house, six to nine 24-h measurements were carried out, spread over the year and the laying cycle. Upstream and downstream of the systems, we measured PM10, PM2.5, and carbon dioxide concentrations, temperature, and relative humidity. Additional measurements of particle size distribution only were carried out at the DF of another poultry house. The latter showed that removal of PM by the DF increased with increasing particle diameter. Mean removal efficiency of the DF for PM10 was 40.1%, whereas PM2.5 was not significantly removed. The ESP reduced concentrations of PM10 by an average of 57.0% and concentrations of PM2.5 by an average of 45.3%. For neither of the two systems an effect of upstream PM concentration on removal performance was found. Results of this study are compared with the available literature and possibilities to improve removal performance are discussed. The mean (SD between houses) untreated emissions rate from the non-cage layer houses was 7.81 (4.12) mg PM10 h−1 bird−1 and 0.44 (0.28) mg PM2.5 h−1 bird−1. In conclusion, the evaluated systems show potential to reduce PM emissions from poultry houses.

Equivalence testing of filter-based, beta-attenuation, TEOM, and light-scattering devices for measurement of PM10 concentration in animal houses

Emissions of particulate matter (PM) from poultry and pig houses may contribute significantly to ambient concentrations. Yet, our knowledge on the accuracy and comparability of samplers available for measuring the high PM10 concentrations (>100μgm–3) in the inside air directly upstream of the ventilation exhausts of these buildings is very limited. The aim of this study was to provide insight into this matter for five candidate samplers: a filter-based cyclone sampler (CYS), the Thermo Scientific FH 62 I-R beta-attenuation sampler (BAS), the Thermo Scientific Tapered Element Oscillating Microbalance, model 1400ab (TEOM), the TSI DustTrak model 8520 (DT), and the GRIMM Portable Aerosol Spectrometer model 1.109 (PAS). Equivalence tests were carried out following European Standard EN 12341 using two devices for each candidate sampler (CAS) and four filter-based low-volume reference samplers (RES). Measurements were performed inside three major animal housings (a fattening pig house, a laying hen house, and a broiler house) and inside an office room. Our key results and conclusions are: (1) neither one of the five CASs, nor the RES itself, met the EN 12341 requirement for comparability between devices of the same sampler type. Using a less strict boundary for this aspect – in concert with performing duplicate sampling – may be appropriate. (2) The CYS met the EN 12341 accuracy requirements in pigs and layers, but overestimated the RES concentration in broilers. The BAS, TEOM, and DT underestimated, and the PAS overestimated, RES concentrations in a systematic manner. The use of correction factors seems to be a promising method to calibrate measured values to RES concentrations. (3) The BAS, TEOM, DT, and PAS started to show scattered regression after 432–500h of sampling, which stresses the need for shortened time intervals between full services. In conclusion, some of the samplers tested could be regarded acceptable when appropriate measures (such as duplicate sampling, correction factors, and more frequent servicing) are applied.

Airborne Particulate Matter and Culturable Bacteria Reduction from Spraying Slightly Acidic Electrolyzed Water in an Experimental Aviary Laying-Hen Housing Chamber

Abstract. Compared to conventional cage laying-hen houses, aviary hen houses generally have much higher concentrations of airborne dust and bacteria due to generation of bioaerosols by the hens’ access to and activities on the litter floor. Hence, reducing these airborne agents is important to safeguard the health of the animals and workers in such housing systems. Spraying slightly acidic electrolyzed water (SAEW) is a novel approach to reducing airborne culturable bacteria (CB) and particulate matter (PM) levels in hen houses. The objective of this study was to evaluate the efficacy of reducing airborne CB and PM in an experimental aviary chamber by periodic spraying of SAEW (Trt), as compared to no spraying (Ctrl ns ) or spraying of tap water (Ctrl w ). The hens were provided 16 h light and 8 h dark (lights on at 6:00 h and off at 22:00 h) and were given access to the litter floor from 12:00 h to 22:00 h. The Trt regimen sprayed SAEW at 14:00 h for 15 min at a dosage of 80 mL m -2 ; the Ctrl ns regimen had no spraying; and the Ctrl w regimen sprayed tap water following the same procedure as with Trt. Concentrations of airborne CB and PM in six aerodynamic size ranges (0.65-1.1, 1.1-2.1, 2.1-3.3, 3.3-4.7, 4.7-7.1, and >7.1 I¼m) were measured at 1.5 m above the floor in the center of the room during the periods of 13:45-14:00 h and 14:45-15:00 h. Compared to Ctrl ns , spraying SAEW significantly reduced airborne CB (>2.1 I¼m) by up to 49% ±10% (p w did not show a reduction effect. No significant difference was found between Trt and Ctrl w in reducing airborne PM, although both reduced or tended to suppress PM >7.1 I¼m in size. The results show that spraying SAEW can inactivate airborne CB attached to PM. Thus, this is a promising technique for alleviating the adverse health impacts of bioaerosols in aviary laying-hen housing systems.

Ammonia, Greenhouse Gas, and Particulate Matter Emissions of Aviary Layer Houses in the Midwestern U.S.

<abstract><title><italic>Abstract.</italic></title> There has been an increased interest in alternative housing for laying hens in certain parts of the world, including the U.S. Associated with the movement are many questions concerning sustainability of such systems. This study continually quantified concentrations and emissions of ammonia (NH₃), carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and particulate matter (PM₁₀ and PM_2.5) for two side-by-side aviary barns each housing 50,000 Hy-Line brown laying hens, located in the Midwestern U.S. The gaseous concentrations were continually monitored using an infrared photoacoustic multi-gas analyzer, while the PM concentrations were measured with tapered element oscillating microbalances (TEOMs). Barn ventilation rate was determined by monitoring the operation time of ventilation fans that had been calibrated in situ. Nineteen consecutive months of monitored data (June 2010 to December 2011) are analyzed and presented. Daily indoor aerial concentrations (mean ±SD) were 8.7 (±8.4) ppm NH₃, 1,636 (±1,022) ppm CO₂, 10.0 (±6.8) ppm CH₄, 2.3 (±1.6) mg m^-3 PM₁₀, and 0.25 (±0.26) mg m^-3 PM_2.5. The aerial emissions are expressed as quantities per hen, per animal unit (AU, 500 kg body weight), and per kg egg output. Daily emission rates (g bird^-1) were 0.15 (±0.08) NH₃, 75 (±15) CO₂, 0.09 (±0.08) CH₄, 0.11 (±0.04) PM₁₀, and 0.008 (±0.006) PM_2.5. The results were compared to reported emission values for conventional (high-rise and manure-belt cage) U.S. laying-hen housing systems. Data from this study provide baseline concentration and emission values for the aviary housing system in the Midwestern U.S., which will also contribute to improvement of the U.S. national air emissions inventory for farm animal operations.

Free chlorine loss during spraying of membraneless acidic electrolyzed water and its antimicrobial effect on airborne bacteria from poultry house.

Spray-application of membraneless acidic electrolyzed water (MLAEW) is a novel technique for disinfection in livestock houses. This study investigated the loss of free chlorine (FC - the major germicidal component in MLAEW) over distance during spraying, as affected by air temperature and initial FC concentration. The anti-microbial effect of MLAEW on airborne bacteria from an aviary laying-hen house was examined. MLAEW was prepared at two FC concentrations: app. 15 and 60 mg L⁻¹, and sprayed at three air temperatures (18, 25, 32 °C). The original MLAEW solution and MLAEW aerosols collected at 0, 25, and 50 cm from the spray nozzle were analyzed for FC concentrations. Bacteria were immersed into these MLAEW samples and numerated for viable count after 0.5, 2 and 5-min treatments. MLAEW aerosols collected at 0 cm lost 11.7-13.2% FC, compared with the original MLAEW solution. This initial loss was affected neither by the initial FC concentration (P = 0.13) nor by air temperature (P = 0.57). The rate of FC loss during travelling was 0.79-0.87 % per cm of aerosol travel distance (% cm⁻¹) at 18 °C, 1.08-1.15 % cm⁻¹ at 25 °C, and 1.35-1.49% cm⁻¹ at 32 °C. This travelling loss was affected by air temperature (P = 0.02), but not by initial FC concentration (P = 0.38). Bacteria were completely inactivated at 0.5 min when treated with MLAEW samples with FC > 16.8 mg L⁻¹, in 2 min when FC > 13.8 mg L⁻¹, and in 5 min when FC > 7.2 mg L⁻¹. Airborne bacteria from aviary hen house can be effectively inactivated by MLAEW with adequate FC concentration and contact time. During spraying, the anti-microbial efficacy of MLAEW aerosols decreased over distance due to FC loss which exacerbated at higher air temperatures.

Thermal Environment, Ammonia Concentrations, and Ammonia Emissions of Aviary Houses with White Laying Hens

Abstract. Maintaining comfortable thermal environments and good indoor air quality is essential to ensuring optimal production performance, welfare, and health of animals. Alternative laying-hen housing systems are being adopted by some egg producers in the U.S. However, information on indoor thermal and aerial environments of such alternative housing systems is meager. This article reports a one-year monitoring of thermal conditions (air temperature and relative humidity or RH) and ammonia (NH 3 ) concentrations and emissions of four aviary laying-hen houses (same dimensions, manure belt plus litter floor systems, 50,000-hen capacity each) at a commercial farm in the Midwest U.S. Carbon dioxide (CO 2 ) concentrations at the air inlet and near the exhaust fans were measured and used, along with literature values of the metabolic rates of the hens, to estimate building ventilation rate (VR). The results show that indoor temperature, RH, CO 2 concentration, NH 3 concentration, and VR of the four houses (mean ±standard deviation) were 23.4°C ±0.3°C, 64% ±3%, 1520 ±87 ppm, 5.2 ±0.4 ppm, and 4.5 ±0.6 m 3 h -1 hen -1 , respectively. The highest daily mean NH 3 concentration was 13 ppm (and 20 ppm within the day) in winter. The NH 3 emission rate was 0.14 ±0.01 g d -1 hen -1 . These values of NH 3 concentrations and emissions were lower than those reported for European aviary houses. The NH 3 emissions of the monitored aviary houses in this study are comparable to those of U.S. manure-belt cage houses, but are much lower than those of U.S. high-rise cage houses. The magnitude of NH 3 emissions observed in this study was consistent with that of similar aviary houses with brown hens in another extended field measurement in the same region.

Airborne bacterial reduction by spraying slightly acidic electrolyzed water in a laying-hen house

Spraying slightly acidic electrolyzed water (SAEW) has been considered as a potential approach to reduce airborne bacteria in laying-hen houses. In this study, the effects of spraying SAEW on airborne bacterial reduction were investigated in a laying-hen house as compared with using diluted didecyl dimethyl ammonium bromide (DDAB). Averaged air temperature reduced by approximate 1 °C and average relative humidity increased by 3% at a stable ventilation rate (about 2.5 m3 hr−1 per bird) in the laying-hen house 30 min after spraying (120 mL m−2). Compared with the control without spraying, the airborne bacterial concentration was reduced by about 0.70 and 0.37 log10 colony-forming units (CFU) m−3 in the 4 hr after spraying 120 mL m−2 SAEW (available chlorine concentration [ACC] of 156 mg L−1) and diluted DDAB (active compound concentration of 167 mg L−1), respectively. Compared with spraying diluted DDAB, spraying SAEW was determined to be more effective for reducing airborne bacterial in laying-hen houses. The effects of spraying SAEW and diluted DDAB on airborne bacterial reduction in the laying-hen house increased with the increasing available chlorine concentrations for SAEW (156, 206, 262 mg L−1) and increasing active compound concentrations for diluted DDAB (167, 333, 500 mg L−1), respectively. Spraying SAEW and diluted DDAB with two levels of spraying volumes (120 and 90 mL m−2) both showed significant differences on airborne bacterial reduction in the laying-hen house (P < 0.05). Implications: It is difficult to effectively reduce airborne bacteria in laying-hen houses. This work describes the application of spraying slightly acidic electrolyzed water as a new approach for reducing airborne bacteria in a laying-hen house. The effects of active compound concentrations and spray volumes on the airborne bacterial reductions by spraying SAEW were also investigated. This study provided a new effective and environmentally friendly approach to reduce the airborne bacteria in poultry houses, contributing to bird housing environment management and improving bird health.