Ammonia production in poultry houses can affect health of humans, birds, and the environment—techniques for its reduction during poultry production

Due to greater consumption of poultry products and an increase in exports, more poultry houses will be needed. Therefore, it is important to investigate ways that poultry facilities can coexist in close proximity to residential areas without odors and environmental challenges. Ammonia (NH 3 ) is the greatest concern for environmental pollution from poultry production. When birds consume protein, they produce uric acid, ultimately converted to NH 3 under favorable conditions. Factors that increase production include pH, temperature, moisture content, litter type, bird age, manure age, relative humidity, and ventilation rate (VR). NH 3 concentration and emissions in poultry houses depend on VR; seasons also have effects on NH 3 production. Modern ventilation systems can minimize NH 3 in enclosed production spaces quickly but increase its emissions to the environment. NH 3 adversely affects the ecosystem, environment, and health of birds and people. Less than 10 ppm is the ideal limit for exposure, but up to 25 ppm is also not harmful. NH 3 can be minimized by housing type, aerobic and anaerobic conditions, manure handling practices, litter amendment, and diet manipulation without affecting performance and production. Antibiotics can minimize NH 3 , but consumers have concerns about health effects. Administration of probiotics seems to be a useful replacement for antibiotics. More studies have been conducted on broilers, necessitating the need to evaluate the effect of probiotics on NH 3 production in conjunction with laying hen performance and egg quality. This comprehensive review focuses on research from 1950 to 2018.