Instrumentation and procedures have been developed to characterize mechanical ventilation system capacity as part of an evaluation of ammonia emissions from commercial poultry housing. A FANS anemometer array unit, developed at the Mississippi USDA center, built and refined at University of Kentucky, and calibrated at the BESS laboratory, was found to have repeatability in the range of about 1% between two traverse readings performed one after the other. The unit was used to measure broiler house fans under typical system static pressure differences. A hydraulic lift cart was fabricated to streamline FANS positioning and movement through the large poultry houses. Taping all gaps between the FANS unit and fan housing improved airflow measurements about 6% versus not taping. Using a duct to transition down to 36-inch fans resulted in a 2.5% improvement versus not using a duct. Fan manufacturer performance data was 2 to 13% higher than actual field performance.