Technical Abstract: Ammonia generation in poultry houses results from the natural breakdown of litter (bedding material mixed with deposits of feces, feathers, spilled feed and water). Good management practices can reduce ammonia concentrations in poultry houses. This factsheet relates findings from a recent publication that shows there is a critical litter moisture level at which ammonia generation is maximized. Relative to the findings, the major focus for house and litter management lies with litter moisture control. Growers should manage houses to avoid unnecessary water inputs to the litter by maintaining leak-free watering systems, properly operated evaporative cooling pads, and preventing condensation on interior house surfaces. Attaining lower litter moisture can be accomplished with minimal additional cost to the grower. Improved profits from improved production can be substantial. For 50 ppm ammonia exposure, body weights of 7 week old birds were reduced by 0.5 lb compared to 25 ppm ammonia. Applying 2010 production statistics from the National Agricultural Statistics Service shows increasing average broiler weight by just 0.1 lb in 10% of U.S. integrators would add $41.5 million to grower profits.