Ammonia and poultry welfare: a review

Atmospheric ammonia is a major aerial pollutant of poultry buildings. The c urrent exposure limits for ammonia of 25 ppm are set on the basis of human safety rather than animal welfare. This paper reviews the evidence for ammo nia exposure affecting various aspects of poultry welfare. The reviewed evi dence suggests that ammonia exposure (1) causes irritation to the mucous me mbranes in the eyes and the respiratory system; (2) can increase the suscep tibility to respiratory diseases; and (3) may affect food intake, food conv ersion efficiency and growth rate. The behavioural effects of ammonia on po ultry have recently been investigated and suggest that there may be a thres hold for ammonia detection or aversion at or below the current exposure lim it. The available evidence for the effects of ammonia on poultry welfare sh ould be considered when setting future guidelines for ammonia exposure in p oultry houses.