Dogs in shelters are exposed to various psychological stressors, including novelty, separation from attachment figures, and noise. Previous studies have shown that shelter living produces elevations in hypothalamic–pituitary–activity (HPA) activity and suggest that a dysregulation between pituitary and adrenal activity may occur as a dog’s stay is prolonged. To further examine these issues, we performed a fine-grained analysis of pituitary–adrenal measures over the course of a dog’s first 14 days in a county animal shelter. The effect of diet on hormonal measures was also assessed.