Avoidance of atmospheric ammonia by domestic fowl and the effect of early experience

Secondly, eight flocks of 12 female broiler fowl were exposed to either 2 or 19 ppm ammonia from 1 to 26 days of age. At 26 days, each flocks, was placed in a preference chamber with access to four compartments and kept at the same atmospheric ammonia concentration (2 or 19 ppm) during an acclimatisation periods of 4 days. Following acclimatisation, a 4-day test was conducted in which the birds were given a choice of compartments containing 4, 12, 20 and 37 ppm ammonia with colour cues. Birds again avoided the two higher ammonia concentrations (F3,15 = 8.54; P = 0.002) and there was no significant interaction between ammonia and previous exposure. Again there was an effect of ammonia on compartment visit duration (Wald statistic = 15.94; d.f. = 3; P = 0.001) but there was no significant interaction between ammonia and previous exposure. Broiler fowl avoid ammonia at concentrations commonly found on poultry units regardless of previous experience, suggesting it to be aversive at concentrations above approximately 10 ppm.