A multi-state, multi-disciplinary project is developing a comprehensive database of ammonia emission rates (ER) from US poultry facilities. The influence of common management strategies and practical means of reducing ammonia (NH3) emissions are under study. The measurement of ER under cold weather conditions from 8 broiler houses with re-used (‘builtup’) litter in Kentucky is described in this paper. Ammonia concentrations were determined using electrochemical sensors; ventilation rate was accurately estimated by monitoring runtime of the ventilation fans whose airflow rates were calibrated with a portable anemometer array, also known as the Fan Assessment Numeration System (FANS). Mean ammonia ER (by site, 2 sequential days, 4 houses) ranged from 0.10 to 0.98 g NH3 bird -1 d -1 . Bird age during ER measurement ranged from 11 to 56 days old. A regression of ER vs bird age is presented. There was high variability for emission rates among the houses, even for houses on the same farm (14-57% coefficient of variation). Day to day variability (consecutive days) was substantially less than house-to-house variability for the same time period, and appeared related to differences in ventilation rates. Additional data are being collected so that there can be a more complete interpretation of the wide range of ER and how it is affected by characteristics including litter re-use, bird and house management, and abatement methods.