Behavioural characteristics of dogs removed from hoarding situations

Hoarding occurs when persons accumulate animals in numbers that exceed their capacity to provide for the needs of the animals. Typical animal hoarding environments are extremely unsanitary and unhealthy, with malnutrition, disease, and death all common elements. Anecdotal reports of dogs recovered from hoarding situations have described a wide array of abnormal behaviours. The purpose of this study was to characterize the differences between dogs recovered from hoarding situations and typical pet dogs. Dogs were recruited in this case-control study through American organizations that rehome animals recovered from hoarding situations. Behavioural evaluations of the dogs were obtained from current owners/fosterers using the Canine Behavioural Assessment and Research Questionnaire (C-BARQ), which utilizes ordinal scales to rate either the intensity or frequency of the dog's behaviours. A total of 408 formerly hoarded dogs were included in the study. Among the hoarded dogs, the male-to-female ratio was 0.82:1, and the dogs had been living in their adoptive homes for an average of 2.2 years (SD = 1.4 years) when the C-BARQ was completed. Twenty-eight behavioural outcomes were compared between formerly hoarded dogs and dogs representing a convenience sample of pets (restricted on the same breeds, age range, and rehoming status as hoarded dogs) to act as controls (n = 11,277). In comparison to the control dogs, formerly hoarded dogs were reported as displaying significantly higher scores related to fear (stranger-directed, dog-directed, and non-social; p < 0.001), sensitivity to touch (p < 0.001), attachment and attention-seeking (after spending at least 2.5 years in a new home; p < 0.001), separation-related behaviours (if there were children in the new home; p = 0.017), urination and defecation when left alone (p < 0.001), and repetitive behaviours (if they were rehomed with other dogs; p < 0.001). Conversely, hoarded dogs were found to have significantly lower scores related to aggression towards strangers (if placed in a new home with no other dogs; p = 0.016) and towards other dogs (if the hoarded dogs were older than 2 years old; p < 0.001), trainability (p < 0.001), chasing small animals (p < 0.001), excitability (only during the first 2.5 years in a new home; p < 0.001), energy (p < 0.001), dog rivalry (p < 0.001), and persistent barking (if rehomed with no other dogs; p < 0.001). Having a better understanding of the abnormal behavioural characteristics of these animals should guide the development of more specific therapeutic approaches to their rehabilitation.