Simple Summary Burgeoning interest in the emotional experiences and cognitive abilities of dogs has led to novel methods to measure and improve canine welfare. Dog toys, in particular, are commonly thought to benefit dogs' mental and physical health. In this study, we examined the effect of introducing new toys to companion dogs. Our results showed a slight improvement in some positive welfare measures in dogs who received more complex toys when compared to dogs who received less complex toys and those who received no toys. However, this difference was not statistically significant and we found no differences in subjects' eating rate or activity levels. While research has found that toys may improve the welfare of kenneled dog populations (shelter- and laboratory-housed dogs), our findings did not find the same to hold with pet dog populations. We discuss the relevance of the study population and the welfare measures used in attempts to study "enrichment" in animals.Abstract Retail dog toys are often provided to companion animals to provide cognitive and physical stimu- lation and improve the animals' quality of life. These toys, sometimes known as "enrichment toys", have been shown to play a role in increasing appetite and activity levels and decreasing undesirable behaviors (e.g., barking, self-isolating behaviors) in some domestic dog (Canis familiaris) populations. In this study, we evaluate the effect of toys on appetite, activity levels, and positive affective states as measures of well- being in companion dogs. Behaviors were compared before and after regular interactions with different types of toys over twelve days. We found that provisioning companion dogs with toys did not significantly alter their activity level, rate of food consumption, or cognitive bias. While dogs who received more complex toys showed a slightly improved cognitive bias, there were no significant differences in behaviors be- tween the subjects who received "less complex" toys (e.g., a bone, ball) and "more complex" toys (e.g., puzzle toys). We conclude with reflections on the relevance of our subject population to the result seen, and on the different forms of the cognitive bias test.
