Evaluating pair versus solitary housing in kennelled domestic dogs (Canis familiaris) using behaviour and hair cortisol: a pilot study

Numerous studies conducted to assess welfare of domestic dogs housed in kennel facilities have reported that these dogs experience suboptimal living conditions. One important goal of improving welfare of kennelled dogs is to reduce their stress levels, and one recommended approach for improving welfare of kennelled dogs is group or social housing. The beneficial effects of management changes designed to achieve this goal should be measurable in individual animals. Stress is evident through behaviours exhibited, as well as via the concentration of cortisol, a key hormone reflecting stress. Using behavioural and hair cortisol measures, we conducted a pilot study to measure the impact of switching dogs housed in a long-term kennels facility from solitary to pair housing, using both within-subjects and between-groups comparisons. Considerable individual variation in dog responses was noted, with only two of eight pair-housed dogs showing significant declines in multiple stress-related behaviours once in pair housing. The most sensitive behaviours were active vigilance and repetitive movements (such as jumping and pacing). Barking was reduced overall in the facility following the housing change, even among dogs still in solitary housing. The long-term stress as reflected in hormone deposition in hair also provided encouraging indications that the dogs experienced lower stress levels when in paired housing; dogs showed a significant decline in hair cortisol levels from the first (prehousing change) to second (postintervention) samples. Domestic dogs are social animals, and numerous indications of potential benefit were recorded with no negative impacts seen. Based on our findings, we recommend pair or group housing of compatible dogs as a promising addition to the strategies available to those seeking to improve welfare of kennelled dogs. Future studies using higher numbers of animals and that include tracking of hair cortisol, vigilance behaviour, repetitive movements and barking would be desirable.