2013 - 2018

Impact of ammonia on the welfare of poultry

Principal Investigator: Alexandra Harlander-Matauschek, University of Guelph
Co-investigator: Tina Widowski, University of Guelph; Bill Van Heyst, University of Guelph; James Squires, University of Guelph; Stephanie Torrey, University of Guelph
Status: Completed


To investigate the effects of manure, the main source of ammonia emissions in poultry housing, on the health and welfare of the birds, as well as help set targets for appropriate in-barn emission levels.


Ammonia is a noxious gas associated with poultry manure that is produced from microbial decomposition of nitrogenous compounds, especially from uric acid within the manure.  There are three potential modes by which poultry may be exposed to manure and manure gas (through volatized ammonia, direct contact of the dermis and oral route) and it is not always clear to what extent each route of exposure impacts or adversely affects bird health and behaviour.  Elevated concentrations of ammonia results in negative health outcomes that could lead to a reduced or altered sensory input from the environment, which may in turn effect behaviour.  Oral exposure, by which manure and ammonia contact poultry is less well documented and often overlooked. The ability of an animal to directly respond and adjust its behaviour to environmental stimuli is defined as behavioural flexibility.  Behavioural flexibility reflects the degree to which behaviour is guided by stimuli from the environment.  Poultry species living in complex social and physical environments require some degree of behavioural flexibility.  It could be assumed that chronic exposure to external stressors such as manure and manure gas alters bird’s physiology and responses to external stimuli. Although, there are numerous strategies to mitigate ammonia emissions from poultry facilities, most of these approaches involve controlling ammonia from interacting with nitrogen after it has been excreted from the bird.  Additionally, low crude protein diets can effectively reduce nitrogen in the excreta with less potential for microbial conversion to ammonia.  The outcome of feeding low-protein diets to reduce nitrogen in the faeces, in terms of fatty-livers, on bird health and welfare has never been examined. To date, the majority of research on the adverse effects of manure on poultry has focused on the effects of atmospheric ammonia on bird performance and damage to mucosa, respiratory tract or integument as well as the ability of birds to detect and avoid ammonia concentrations in the air.  No studies have addressed bird’s behavioural preferences in regards to manure and manure gas; this represents a significant knowledge gap.  Therefore, the goal of this research is to address this deficit by testing whether relevant concentrations of manure and manure gas influence behaviour and health of birds.  More specific in the proposed research we aim to determine whether contact with manure keeps poultry healthy and/or provides the birds with what they apparently want.


$598,301 (AAFC/CPRC $558,301*, Egg Farmers of Canada $40,000)


*This research was part of the Poultry Science Cluster 2 which was supported by AAFC as part of Growing Forward 2, a federal-provincial-territorial initiative.

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