Tunnel-ventilated Broiler Houses Research Articles

Managemental Impacts on Particulate Matter Emission in Tunnel-Ventilated Broiler Houses

In livestock houses, particulate matter (PM) is a critical factor not only for disease and odor spread but also for the work environment. In particular, workers are exposed to high concentrations of organic particulate matter and harmful gases while performing their tasks, and, as they age, they become more vulnerable to respiratory diseases. This study analyzed the PM concentrations in commercial broiler houses, focusing on the differences in ventilation rates according to the season and the type of work, categorized into a static work period (SWP) and dynamic work period (DWP). In the regional monitoring using gravimetric methods, the average PM concentrations were found to be within acceptable limits, with TSP at 1042 µg/m3, PM-10 at 718 µg/m3, and PM-2.5 at 137 µg/m3. These values did not exceed the recommended exposure limits for inhalable dust at 2400 µg/m3 and respirable dust at 160 µg/m3 in chicken farmers. However, in the personal monitoring using a real-time aerosol spectrometer, it was revealed that the aerosol concentrations during DWP exceeded the standards by up to 214%. Specifically, during DWP, the concentrations were 1.74 times higher for TSP, 1.40 times higher for PM-10, and 1.22 times higher for PM-2.5 compared to SWP. It was observed that during the movement of workers, the physical generation of particles around 10 µm, such as feed and bedding, occurred due to the movement of chickens, which influenced the aerosol concentration.

Broiler Welfare and Meat Production Efficiency in Tunnel Ventilated Environmental Control Vis-a- Vis Conventional Open Sided Shed under Different Stocking Densities

Present study was conducted to compare welfare and associated meat production performance and quality of broiler in open sided conventional broiler house (OSCBH) with floor space allowance of 1.0/ft2 per chick and in tunnel ventilated environment control broiler house (ECBH) with reducing floor space of 1.0, 0.9, 0.8, 0.7and 0.6 ft2 per chick. Average body lesions score, indicating physical injury and welfare were well within the acceptable limits of European welfare quality protocol. Stress related anti-oxidant enzyme (Glutathione peroxidase, Lipid peroxidation, Superoxide dismutase, Catalase and Glucose-6-phosphate dehydrogenase) concentrations were higher in OSCBH (T0)) than ECBH (T1, T2, T3, T4 and T5). However percent eviscerated carcass and prime cuts did not decreased significantly (p≤ 0.05) in ECBH at higher stocking densities but meat yield per unit floor area was around 90 % higher even at 40% reduction of floor allowance.

Assessment of ammonia and greenhouse gas emissions from broiler houses in Portugal

Broiler husbandry is a significant source of ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) emissions but scarce studies have been made under Mediterranean conditions. The aim of this study was to evaluate the NH3, N2O, CO2 and CH4 emissions on commercial broiler houses under Portuguese winter conditions. The study was made on a commercial broiler farm located in central Portugal. Three tunnel ventilated broiler houses with similar equipment and production practices were selected. The outdoor and indoor environmental conditions, gas concentrations and ventilation rates of each broiler house were measured during 42 days of growing cycle. Results showed that the maximum concentrations of NH3, N2O, CO2 and CH4 did not exceed the threshold values recommended to maintain indoor air quality on broiler houses. The average emission rates from broiler houses under winter conditions were 0.13 ± 0.04, 0.041 ± 0.002, 96.2 ± 8.8 and 0.226 ± 0.013 g day−1 bird−1 (22.0 ± 7.3, 6.7 ± 0.3, 16,028 ± 1465 and 37.7 ± 2.1 g day−1 LU−1) for NH3, N2O, CO2 and CH4, respectively. Furthermore, NH3 and N2O emission rates of this study are in the same range than measurements from most European countries, but CH4 emission rate seems higher to those reported for Mediterranean countries.

Measurement and Numerical Simulation of Air Velocity in a Tunnel-Ventilated Broiler House

A building needs to be designed for the whole period of its useful life according to its requirements. However, future climate predictions involve some uncertainty. Thus, several sustainable strategies of adaptation need to be incorporated after the initial design. In this sense, tunnel ventilation in broiler houses provides high air velocity values (2–3 m·s−1) at animal level to diminish their thermal stress and associated mortality. This ventilation system was experimentally incorporated into a Mediterranean climate. The aim was to resolve these thermal problems in hot seasons, as (traditional) cross-mechanical ventilation does not provide enough air velocity values. Surprisingly, very little information on tunnel ventilation systems is available, especially in terms of air velocity. Using Computational Fluid Dynamics (CFD) and a multi-sensor system, the average results are similar (at animal level: 1.59 ± 0.68 m·s−1 for CFD and 1.55 ± 0.66 m·s−1 for measurements). The ANOVA for validation concluded that the use of CFD or measurements is not significant (p-value = 0.1155). Nevertheless, some problems with air velocity distribution were found and need to be solved. To this end, CFD techniques can help by means of virtual designs and scenarios providing information for the whole indoor space.

Cooling Broiler Chickens by Surface Wetting: Indoor Thermal Environment, Water Usage,and Bird Performance

Abstract. A surface-wetting cooling system was evaluated and compared to a conventional evaporative cooling system in commercial, tunnel-ventilated broiler houses during five flocks in summer months over three years. Surface wetting (accomplished using low pressure sprinklers, SPRK) and a conventional evaporative pad cooling system (PAD) were employed in adjacent houses at the University of Arkansas Applied Broiler Research Farm. With SPRK, overhead sprinklers were spaced evenly 6 m apart and 1.2 to 2.4 m above the litter surface and were intermittently operated to apply controlled volumes of large water droplets onto the birds. The SPRK house had substantially higher air temperature but lower relative humidity compared to the PAD house during critical supplemental cooling periods. During a 2-day heat stress period, the core body temperatures of birds in the SPRK house were similar to those of birds in the PAD house. The bird live weight and livability were not significantly different between SPRK and PAD with feed conversion being better in the SPRK treatment. No correlations were found between daily mortality and either daily maximum ambient temperature or flock age, indicating both cooling systems were effective in relieving heat stress of broiler chickens. Apparently, the evaporation of sprinkled water from the bird’s surface, benefiting from favorable convective conditions (intrinsically high air velocity of tunnel ventilation) and lower relative humidity, was able to compensate for higher temperatures measured in the SPRK house. Final litter moisture conditions were not significantly different. Due to the nature of the water delivery, cooling water usage per bird basis in SPRK was significantly less than that used by PAD (water in SPRK averaged 33% of that used in PAD). This represents a major opportunity for water conservation in broiler production.

Factors Associated with Introduction of Infectious Laryngotracheitis Virus on Broiler Farms During a Localized Outbreak

We analyzed factors involved in the introduction of infectious laryngotracheitis (ILT) virus (ILTV) onto broiler farms during a localized outbreak in an immunologically naive broiler population. The outbreak occurred in the state of Mississippi, United States in 2002-2003. From the responses to a retrospective survey questionnaire administered via personal interviews, 181 farm-level risk factors were defined and analyzed for their association with ILTV introduction using logistic regression. There were 27 case farms (93% of all the infected broiler farms) and two sets of controls: farms matched to the cases by location and those randomly selected among the broiler farms in Mississippi. We found that farm suppliers such as gas company representatives, who are likely to visit other farms, and farm-workers who visit other chicken farms, are likely vehicles of ILTV introduction onto broiler farms. These risks can be greatly reduced by following biosecurity procedures, in particular if farm workers bathe and change footwear prior to entering broiler houses on their own farm. Footbaths for farm visitors can provide a false sense of security during an ILT outbreak when, indeed, other practices such as plastic boots or changing boots are more effective in preventing ILTV transmission. Sharing of equipment used for removal of caked broiler litter between subsequent flocks may also serve as an important vehicle of ILTV transmission. During the 2002-2003 outbreak, shared litter removal equipment was associated with ILTV transmission despite a requirement being put in place for litter decontamination. We also found that tunnel-ventilated broiler houses with inlets toward a neighboring poultry farm are more likely to get infected with ILTV. In addition to this analysis, the data collected provide a good overview of the actual practices and deficiencies of biosecurity undertaken on broiler farms in this part of the United States.

Ammonia emissions in tunnel-ventilated broiler houses

Gas production in broiler houses and their emissions are closely related to the microclimate established inside the house according to air temperature, humidity, and velocity. Therefore, the internal house environment is influenced by building typology and ventilation system. The objective of the present study was to evaluate ammonia emission rates in broiler houses equipped with different ventilation systems (negative or positive pressure) and litter conditions (new or built-up). The environment of six commercial broiler houses was evaluated internal and external NH3 concentrations. Ventilation rates were recorded to estimate ammonia emission rates. The efficiency of circulation and exhaust fans was assessed, and higher ventilation rates were determined in negative-pressure houses due to the higher flow of the fans. Houses with new litter increased ammonia emission rates along the rearing period, indicating the relationship between gas emissions, bird age and ventilation rates, and presented a typical curve of NH3 emission increase. Negative-pressure houses with built-up litter presented higher emission rates during the first rearing week due to the high NH3 concentration during the brooding period, when the ventilation rates required to maintain chick thermal comfort are low. Although the results of the present study indicate an advantage of the positive-pressure systems as to gas emissions, further research is needed reduce gas emissions in broiler houses with negative-pressure systems.

Ammonia Emission Factors from Broiler Litter in Barns, in Storage, and after Land Application

We measured NH₃ emissions from litter in broiler houses, during storage, and after land application and conducted a mass balance of N in poultry houses. Four state-of-the-art tunnel-ventilated broiler houses in northwest Arkansas were equipped with NH₃ sensors, anemometers, and data loggers to continuously record NH₃ concentrations and ventilation for 1 yr. Gaseous fluxes of NH₃, N₂O, CH₄, and CO₂ from litter were measured. Nitrogen (N) inputs and outputs were quantified. Ammonia emissions during storage and after land application were measured. Ammonia emissions during the flock averaged approximately 15.2 kg per day-house (equivalent to 28.3 g NH₃per bird marketed). Emissions between flocks equaled 9.09 g NH₃ per bird. Hence, in-house NH₃ emissions were 37.5 g NH₃ per bird, or 14.5 g kg(-1) bird marketed (50-d-old birds). The mass balance study showed N inputs for the year to the four houses totaled 71,340 kg N, with inputs from bedding, chicks, and feed equal to 303, 602, and 70,435 kg, respectively (equivalent to 0.60, 1.19, and 139.56 g N per bird). Nitrogen outputs totaled 70,396 kg N. Annual N output from birds marketed, NH₃ emissions, litter or cake, mortality, and NO₂ emissions was 39,485, 15,571, 14,464, 635, and 241 kg N, respectively (equivalent to 78.2, 30.8, 28.7, 1.3, and 0.5 g N per bird). The percent N recovery for the N mass balance study was 98.8%. Ammonia emissions from stacked litter during a 16-d storage period were 172 g Mg(-1) litter, which is equivalent to 0.18 g NH₃ per bird. Ammonia losses from poultry litter broadcast to pastures were 34 kg N ha (equivalent to 15% of total N applied or 7.91 g NH₃ per bird). When the litter was incorporated into the pasture using a new knifing technique, NH₃ losses were virtually zero. The total NH₃ emission factor for broilers measured in this study, which includes losses in-house, during storage, and after land application, was 45.6 g NH₃ per bird marketed.

Comparison of ammonia measurement methods inside and outside tunnel-ventilated broiler houses

SUMMARY Accurately measuring NH3 produced from poultry litter and emitted from mechanically ventilated broiler houses continues to be a challenge. Many technologies and methods are available to measure NH3, with costs ranging from inexpensive (but rather inaccurate, such as colorimetric tubes) to expensive (for precision analytical equipment such as laser spectrometers). This study investigated the variability among selected low, midrange, and high-cost instruments. Inter-instrument and intra-instrument comparisons were made using colorimetric pull tubes and dosimeter tubes, electrochemical sensors, and tunable-diode open-path laser spectrometers (OPL). This study consisted of inside and outside broiler house studies to evaluate instrument performance under different environmental conditions and NH3 concentrations. The OPL showed the least variation during the in-house and outside comparisons. The electrochemical sensors and colorimetric tubes performed well at NH3 levels typically found in a properly ventilated broiler house. With no ventilation, variation among instruments increased as NH3 concentrations increased. With the exception of the OPL, concentrations on the outside were too low and environmental elements were too harsh for these instruments to perform well.

Long axis heat distribution in a tunnel-ventilated broiler house equipped with an evaporative pad cooling system

Chicken meat and egg production in the Çukurova region of Southern Turkey shows enormous potential for growth. However, high temperatures in summer pose serious difficulties for these types of production. Evaporative pad cooling systems have been used to minimise rises in temperature and are commonly used in poultry houses in this region. The change of air temperature from the entry point to the system through the pads, to the exit point of the broiler house was investigated in this study. Experiments were carried out in a tunnel-ventilated broiler house in the Çukurova region. The broiler house has the capacity to house 15 000 chicks with a floor area of 70 by 12 m. In this experiment, the broiler house incorporated 15-cm-thick cellulose-based pads. Results obtained in August–September 2007 revealed a cooling efficiency of 69.35%, a 5.19°C decrease from the outside air temperature after passing through the pads, and a 1.52°C increase in air temperature at the exit point, which was located at the end of the broiler house.

Fine Particle Measurements Inside and Outside Tunnel-Ventilated Broiler Houses

Emissions from animal feeding operations have become a growing concern. Although many studies describe occupational exposures and exhaust concentrations associated with animal facilities, very little information has been provided about the ambient air around the houses. This study investigates real-time and primarily 24-h time-integrated levels of particulate matter ≤2.5 μm in diameter inside and outside (up to 500 ft from the house) of commercial tunnel-ventilated broiler houses on a farm in northeast Georgia. None of the 24-h particulate matter measures collected when the houses were tunnel ventilated exceeded the Environmental Protection Agency's 24-h National Ambient Air Quality Standard of 65 μg/m3.

Dietary Amino Acid and Sodium Bicarbonate Responses in Broilers Reared in Hot Environmental Temperatures

Better environmentally controlled broiler houses have resulted in many integrated broiler operations using the same dietary feed formulations in winter and summer months due to only minor differences in environmental temperature in the broiler house. Much research has addressed broiler nutrient needs in thermoneutral vs. hot temperature conditions, but research evaluating nutrient needs of broilers during moderate temperature conditions (tunnel-ventilated houses during summer months) is lacking. This study evaluates the impact of increasing dietary Lys and other essential amino acids, and the addition of dietary sodium bicarbonate in high and moderate temperature conditions. Experiment 1 was conducted in batteries and evaluated broiler nutritional responses (d 20 to 40) in hot-cyclic temperature conditions (26 to 34°C). Experiment 2 was conducted in floor pens and evaluated broiler nutritional responses (d 37 to 49) in environmental temperature ranges that mimic a tunnel-ventilated broiler house during summer months (26 to 31°C). In both experiments, dietary treatments had minimal impact on live performance and breast meat yield. Lower mortality (P < 0.06), however, was observed in broilers fed the low CP diet in the hot temperature environment.

PARTICULATE MATTER AND AMMONIA EMISSION FACTORS FOR TUNNEL–VENTILATED BROILER PRODUCTION HOUSES IN THE SOUTHERN U.S.

Emissions rates for particulate matter less than 10 .m (PM10) and ammonia (NH3) from commercial tunnel–ventilated broiler houses in central Texas were analyzed using linear regressions to develop emission rates as a function of bird weight for broilers on litter. Interior ambient temperature and relative humidity were not found to be significant factors affecting emissions. From the regression equations, emission rates for PM10 and NH3 for average weight birds in these facilities were estimated. Over a 7–week grow–out period, the average bird weight was estimated to be 1.03 kg, the average emission rate for PM10 was 26.5 mg PM10 bird–1 day–1, and the average emision rate for NH3 was 632 mg bird–1 day–1. The emission factor was defined as the total emission in mass per bird for the grow–out period. For typical production conditions and management, the emission factor for PM10 was 1.3 g PM10 bird–1, and for NH3 the emission factor was 31 g NH3 bird–1. These results were compared to values found in the literature. For a facility comprised of four tunnel–ventilated broiler houses with 27,5000 birds per house and a 2–week idle time between 7–week grow–out periods, the emission inventory was calculated to be 828.2 kg PM10 year–1 and 19,780 kg NH3 year–1. The annual emissions for PM10 were below those required to be reported under the Federal Clean Air Act, and there is currently no requirement for NH3 under this legislation.

CONCENTRATION AND EMISSIONS OF AMMONIA AND PARTICULATE MATTER IN TUNNEL–VENTILATED BROILER HOUSES UNDER SUMMER CONDITIONS IN TEXAS

Total suspended particulate (TSP) concentrations, ammonia (NH3) concentrations, and ventilation rates weremeasured in four commercial, tunnelventilated broiler houses in June through December of 2000 in Brazos County, Texas.TSP and NH3 concentrations ranged from 7,387 to 11,387 .g m3 and 2.02 to 45 ppm, respectively. Ammonia concentrationexhibited a correlation with the age of the birds. Mass median diameters (MMD) of the TSP samples were between 24.0 and26.7 .m aerodynamic equivalent diameter. MMD increased with bird age. The mass fraction of PM10 in the TSP samples wasbetween 2.72% and 8.40% with a mean of 5.94%. Ventilation rates were measured between 0.58 and 89 m3 s1. Measuredconcentrations of PM10 and ammonia were multiplied by the measured ventilation rates to calculate emission rates for PM10and ammonia. Ammonia emission rates varied from 38 to 2105 g hr1. TSP emission rates and PM10 emission rates rangedfrom 7.0 to 1673 g hr1 and 0.58 to 99 g hr1, respectively. Emission rates for ammonia and particulate matter increased withthe age of the birds. Most of the PM in the commercial broiler houses was large enough to be captured by the human or poultryrespiratory system prior to being inhaled into the lungs.

REDUCTION OF POULTRY VENTILATION FAN OUTPUT DUE TO SHUTTERS

Shutters have become standard equipment in tunnel-ventilated broiler houses because they prevent backflowthrough idle fans. This study was done to determine the flow reduction resulting from a shutter on a popular sized[91.4 cm (36 in.)] poultry-house ventilation fan. Results showed that shutters alone (clean condition) reduced fan airflowrates by as much as 10.9% and that dirt accumulation on a fan and shutter (one flock of 42 days) reduced fan airflowrates by as much as 16.3%. After 42 days of rearing broilers, a 91.4 cm (36 in.) diameter ventilation fan and its shuttercan accumulate over 453.6 g (1.0 lb) of dust and dirt. If a fan and shutter were not cleaned between flocks, the flow ratecould be reduced by as much as 23.5% by the end of the second rearing period. The use of a shutter motor designed tofully open the vanes results in a 2.4% improvement in airflow rate compared with a fan/shutter system operating withoutone.

Tunnel-Ventilated Broiler Houses: Broiler Performance and Operating Costs

Interest continues to build in tunnel ventilation as a method of enhancing broiler performance and reducing mortality during warm weather. The perception that operating costs associated with this system may be high has caused concern. The purpose of this study was to collect and compare broiler performance data and operating costs of conventional and tunnel-ventilated broiler houses on a commercial broiler farm. Daily high temperatures during the study averaged 93°F (36°C). Typically, house temperatures were reduced 2 to 4°F (1 to 2°C) in the conventional house and 7 to 12°F (4 to 7°C) in the tunnel-ventilated house. Body weights at 55 days averaged 5.35 lbs. (2.43 kg) in the tunnel-ventilated house and 5.13 lbs. (2.33 kg) in the conventional house. Feed conversion was 2.03 and 2.05 in the tunnel-ventilated and conventional houses, respectively. Livability was essentially the same in both houses. Electricity costs over the entire growout in the tunnel-ventilated houses were nearly double those of the conventional house; however, these costs were only 20 to 30% higher on hot days. Fogging system water usage in the tunnel-ventilated house was more than twice that of the conventional house. Overall, the value of the enhanced performance of the broilers in the tunnel-ventilated house slightly offset the additional operating costs.

Field Calibration of a Transient Model for Broiler Misting

A transient model to predict temperature within a tunnel ventilated broiler house during misting is developed. The model is calibrated with field data to obtain steady-state constants; transient predictions are compared to measured temperatures during cyclic misting for two different size birds. Measured temperatures during cyclic misting are shown to swing between steady-state asymptotes predicted from the model. Transient response of the model was faster than measured temperature data, in part due to temperature sensor dynamic response. The model predicts the length-wise temperature profile within the building during misting, and can be used to investigate alternate misting strategies and designs. Further improvements to the model are suggested.

Mechanical Backup Systems for Electronic Environmental Controllers

A series of mechanical backup systems for electronic environmental controllers is presented for a typical finishing swine barn and a typical tunnel ventilated broiler house. The systems consist of mechanical thermostats and timers used in parallel with the electronic controller, designed to ensure animal survival in the event of controller or related hardware failure. For swine housing, three distinct mechanical backup functions are identified; for broiler housing, four distinct mechanical backup functions are identified. Schematic diagrams of the mechanical backup functions are provided and their implementation is described.