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How much ammonia can chickens tolerate?

Typically, large amounts of ammonia accumulate in confinement poultry operations, peaking when the animals reach market size. The levels can reach as high as 50 parts per million. To see how chickens react to ammonia fumes, scientists exposed them to concentrations of 0, 25, and 45 parts per million. Not surprisingly, the researchers reported that the chickens "foraged, preened, and rested significantly more in the fresh air than in the ammonia-polluted environments." The scientists noted that the hens were equally distraught when the ammonia levels were 25 or 45 ppm, leading them to conclude that "ammonia may be aversive to hens" even at very low concentrations.

The preening pastured hens in the above picture have the good fortune of breathing unpolluted air all of the time. (Coincidentally, these hens laid the eggs that went into the Eggs Florentine in the previous news article. Healthy, contented hens make healthy eggs.)

"The preferences of laying hens for different concentrations of atmospheric ammonia." Applied Animal Behavior and Science, 2000. 68:307-318.

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