The influence of graded levels of atmospheric ammonia on chickens

Abstract

Experiments have been carried out to study the influence of high concentrations of ammonia on the performance of chickens. One hundred parts per million by volume of ammonia caused reductions in the respiration rate of adult hens of between 7 and 24 per cent. Carbon dioxide production and respiratory depth were also reduced. Broiler chickens reared in atmospheres containing high concentrations of ammonia from 28 days of age tended to eat less food than broilers reared in ammonia‐free atmospheres and at 100 p.p.m. of ammonia their growth rate was significantly reduced. Replacement laying pullets reared in atmospheres containing ammonia from 11 to 18 weeks of age, ate less food than similar birds reared in ammonia‐free atmospheres. When the ammonia level was 78 p.p.m. by volume, food consumption was significantly reduced in the period from 15 to 30 weeks of age. This lowered food intake was associated with significantly less live‐weight gain up to 22 weeks of age, and pullets reared in atmospheres with high ammonia concentrations matured up to 2 weeks later than pullets reared in ammonia‐free atmospheres.