Impact of ammonia on welfare of poultry

Principal Investigator

Alexandra Harlander, University of Guelph

Year the work was done


Overall objective

  • Investigate feeding behaviour in relation to the presence of manure.

Specific objectives

  • Study chronic ammonia exposure on physical condition and behaviour on commercial farms.
  • Investigate the effects of atmospheric ammonia on behavioural flexibility.
  • Evaluate the effect of feeding nitrogen-reduced diets on cognitive ability and the risk of fatty liver hemorrhagic syndrome.


  • Laying hens spend less time foraging and were slower to forage in ammoniated environments (25 ppm and 45 ppm of ammonia) compared to being in the fresh air (0 ppm of ammonia).
  • Laying hens behave differently in artificially and naturally sourced air/ammonia (NH3) mixtures.
  • The number of manure belt operations did not affect the number of feeding events in enriched cages.
  • Laying hens are willing to work to gain access to litter substrate and results suggest that laying hens have a relative preference for clean litter (wood shavings) over litter substrate that has been present for the entire duration of their life (unhygienic litter). Laying hens pushed the door with a weight of 1,550 g to gain access to litter substrates.
  • Laying hens more frequently visited and spent more time foraging on excreta-soiled rather than clean scratch pads in enriched cages, demonstrating the importance of foraging substrates in enriched cages.
  • The highest ammonia concentrations were observed during the winter months, reaching a maximum magnitude of 35 ppm.
  • Short-term feeding of nitrogen-reduced diets did not appear to adversely impact behavioural/cognitive abilities in laying hens. In the same study, more than 75% of hens successfully solved the novel motor task assigned to them and successfully reverse the previously learned association, demonstrating behavioural flexibility.
  • Birds demonstrated a clear preference for feeding and foraging on substrate free of excreta. However, still a considerable amount of substrate was consumed from the excreta diets (61.6 g of excreta diet per bird per day). Consumption of excreta did not appear to affect problem solving in hens.


  • This project underwent a major in-course revision resulting in a revised work plan that concentrated on layers.
  • The results should help the poultry industry to adapt to changes in the production systems that may increase the exposure of layers to manure and ammonia and may allow the layer industry to adopt appropriate manure management techniques to maximize bird health and production.

This research applies to

Broilers, Layers, Turkeys

This research was supported by Agriculture and Agri-Food Canada, Canadian Poultry Research Council and Egg Farmers of Canada.