Spatial and temporal variation in ammonia concentrations in broiler sheds: Effects of chicken age and shed type

For studies monitoring ammonia concentrations in chicken sheds, determining a suitable position and height of the monitoring equipment in a shed is important. To investigate this an experiment was conducted in which aerial ammonia concentrations were measured at 10 positions within the shed and three heights (5, 30 and 150 cm above the litter) in conventional and tunnel ventilated sheds at various chicken ages throughout the batch on 8 farms in the Mangrove Mountain and Sydney regions during autumn. All sheds contained chickens on new litter following full cleanout. Position of measurement within the shed had no significant effect on ammonia concentrations, but height above the litter did, with significantly higher ammonia at 5 cm than other heights. Ammonia concentrations remained within acceptable limits (< 25 ppm) throughout, increasing rapidly with chicken age up to week 3 then holding and reducing after week 5. Slightly higher ammonia concentrations were observed in conventional than tunnel ventilated sheds.