Sickness behaviour and its relevance to animal welfare assessment at the group level
The inflammatory response evokes changes in behaviour including increased thermoregulatory activities and sleep, reduced social exploration and appetite, and altered food preferences. This sickness response also includes feelings of lethargy, depression, and pain, collectively referred
to as 'malaise'. Recent experiments involving laboratory rodents reveal information about proximate mechanisms of sickness behaviour, but scant information exists about how sickness behaviour is expressed by farmed species or within social environments. The behavioural needs of ill individuals
differ from those of conspecifics, and failure to accommodate the needs of ill individuals may exacerbate suffering. Policy makers, industry and animal welfare certification programs recommend hospital pens to address the housing and handling needs of ill livestock and to reduce risks of disease
transmission. However, a survey of swine farms in Ontario, Canada revealed deficiencies in the use of hospital pens and gaps in knowledge about best management practices for this vulnerable population. There is considerable scope to improve the welfare and husbandry of ill and at risk animals
through effective use of hospital pens and supportive therapies.