Development of a uniform set of measurement protocols and instrumentation
Principal Investigators (PI-s) at IA, KY and PA are developing minimum acceptable measurement performance criteria for: air temperature and relative humidity (RH), ammonia (NH₃), carbon dioxide (CO₂) and building ventilation rate (VR). A component error analysis will be developed to guide the selection and calibration of sensors used to measure NH₃ emission rate, thus achieving maximum realistic measurement accuracy.

Housing configurations and measurement criteria
The following housing configurations will be selected:

• Pullet houses with manure belts
• Tunnel ventilated layer houses with manure belts
• High-rise layer houses with manure storage, with or without manure boards and scrapers
• Tunnel ventilated broiler houses (winter time cross ventilation)

Measurements of NH₃ emission rates or factors (g NH₃ per bird space per year) will be made for broiler, pullet and layer houses in Iowa (pullets and layers), Kentucky (broilers), and Pennsylvania (pullets, layers, and broilers) during a one year period.

Ventilation rates through the houses, a very critical variable in determination of the emission rate, will be determined. Representative concentrations of the gases (NH₃ and CO₂) inside and outside the houses will be recorded by strategically placed electronic monitors.

NH₃ Measurement
Electrochemical Sensors for NH₃ Concentration. NH₃ will be measured with Draeger PAC III. These are electrochemical-based units, with straightforward calibration procedures and reasonably stable drift characteristics.

Open Loop FTIR Methodology for NH₃ . Stack and volume emission measurement methodologies recently developed, and applied by Bruce Harris (U.S. EPA - Research Triangle Park, NC) and colleagues using area-averaged spectroscopic techniques, will be used in direct comparison to the electrochemical-based, indoor measurements.

Building Ventilation Rate
Direct Measurement of Ventilation Rate with Fans in situ. The automated airflow measurement system developed by collaborator Simmons and colleagues will be used as the primary means of determining ventilation rate for houses with manure storage or litter. The method will be used in conjunction with fan staging data, measured building static pressure, and comparisons made to published fan performance curves where possible. Following calibration, the Fan Performance Data Method outlined below will be used for dynamic measurements.

CO₂ Balance from Inverse Solution of Indirect Calorimetry Heat Production Data. This technique utilizes newly acquired poultry heat production data and measured CO₂ production within the building. Known values of heat production and respiratory quotient, taken from these new data, and measured CO₂ will be used to determine the mass flow rate of air necessary for a balance.

Fan Performance Data Method. This method is the de facto standard method for determining individual fan ventilation rate. When measured static pressure is coupled with motor logger data for fan on/off activity, and a prior calibration, this method can provide the building ventilation rate by means of a simple calibration equation.

Other Variables and Data Logging
Temperature and relative humidity will be obtained from HOBO H8 Pro sensors (Onset Corporation) whose calibrations are individually checked against standard instruments (already available at each station) prior to use, and periodically throughout the tests. Static pressure will be measured using a Setra C2641 connected to a HOBO datalogger. CO₂ concentration will be measured using a Vaisala GMT222 that utilizes an infrared technology. Gas sensor calibrations will be checked according to a schedule recommended by the manufacturer.

Logistics of Field Collection

Logistics diagram of field data collection. Each three-week cycle is repeated 15 times for one full year of data collection and analysis of 8 to 12 poultry houses in each state (KY, IA, PA). Strict transition biosecurity measures (TBM) will be followed between visits to the monitored houses/sites.

As illustrated, each station (IA, KY and PA) will monitor four to six houses weekly in a 3-week cycle (2 weeks on/1 week off), for a total of 12 houses. Upon completion of a 3-wk cycle, the process will be repeated. Strict adherence to biosecurity measures will be followed. The 3-week cycle protocol is intended to create an expanded representative database while at a reasonable instrumentation cost. Continuous measurements (at 6-12 min intervals) from each house will last 3-5 consecutive days during each cycle. Each house will be instrumented for NH₃ emission and related measurements as described above, for a 1-year period. Thus it is expected that about 15 independent periods of measurement will be obtained for each of 12 houses at each station, for a total of 36 houses in the study, giving a total of 2,160 house-days of data.

The number of gas sample measurements taken from each house will depend on the ventilation system configuration. For housing configurations that achieve uniform air distribution and one or more common exhaust areas (such as tunnel ventilated houses), NH₃ and CO₂ sensors will draw air from fans operating continuously to assure well-mixed and representative gas samples. For houses with manure storage or seasonal cross ventilation (e.g. brooding broilers during cool or cold weather), gas samples will be taken at four to six locations within the house. Sensors will be placed near exhaust fans, including those used for minimum ventilation, to ensure representative sampling of exhaust air. Outside conditions for temperature, humidity and CO₂ will also be taken for each site.

To ensure that gas samples are representative of exhaust conditions, air inlets will be inspected and adjusted prior to start of testing. Smoke testing of the air distribution will be conducted as necessary to facilitate adjustments. Where possible, systems that utilize static pressure controlled inlets will be chosen over those systems, which simply operate inlet area proportional to temperature deviation from setpoint. Because the focus of this project is building emission, our main concern will be to obtain representative gas samples from each of the major zones (if more than one exists) in each house.

To maintain this rigorous sampling schedule, given the likely potential for occasional instrumentation failure, the 3-week cycle chosen provides up to 1-week time for data archival, instrumentation repair and calibration, and re-sampling. Further, we have planned to maintain a small supply of replacement equipment (data loggers and sensors) to minimize disruptions caused by instrument failure.

The different methods as outlined above for determining building ventilation rate will be used and compared in these houses. For example, in houses with tunnel ventilation and/or manure belts with uniform indoor environment, the CO₂ balance method will be the primary method for ventilation rate determination. By also measuring building static pressure and fan run-time, and using published fan performance curves augmented with direct measurement of fan flow rates, a validation check of the CO2 balance method will be conducted. For buildings with extended manure storage, a system calibration will be conducted using the direct measurement of fan ventilation rates and building static pressure, thus providing building ventilation rate if static pressure and fan run-time are known.

Treatments
1. Diet manipulation:

Both pullet and layer diets will be formulated with reduced crude protein (CP). Pullets and layers will be provided with one of two diets: either a company standard diet, or an amino-acid (AA) supplemented, reduced CP diet (approximately 19% vs. 18% CP, for pullets and approximately 16.5% vs. 15.5% for layers, respectively).

The precise diets used will be selected based on cooperating company guidelines and interests. In addition to NH3 emission data as described before, production records between these paired houses (bird weight, mortality, and egg production parameters) will be obtained from these industry cooperators. Our intent is to reduce CP below a company's standard level (which is typically in excess by a variable safety margin) while ensuring a properly balanced ration, in order to demonstrate the effect under actual industry conditions.

2. Manure management:

For layer houses: frequency of manure belt or scraper operation, duration since manure storage cleanout, and enzyme treatments (either dietary or direct application to manure).
For broiler houses: frequency and seasonal timing of litter removal, the use of litter amendments to reduce litter pH and general status of litter moisture.
Other innovative bird management/husbandry techniques that indirectly or directly affect manure management include: timing of meals for layers for enhanced manure drying (since manure excretion follows feeding by approximately 4-6h), frequency of replacement of nipple drinkers, and the status of fresh air inlets for minimum ventilation during cool and cold weather.

Information provided by Richard Gates.