Pet hoarding horrors: 27 photos spotlight cruel disorder

Animal hoarding is in the spotlight as a result of some recent high-profile cases, including one that's being called one of the worst in U.S. history. Hoarding is certainly bad for animals, who face malnutrition and squalid conditions that breed disease. And hoarders may be vulnerable to poor air quality and diseases that can be spread from animals to humans.

What causes people to hoard animals ranging from cats to rats? Psychologists don't know the exact causes but point to several factors including early child experiences (parental neglect or abuse), distorted thinking, impulsivity, and plain old loneliness.

Whatever the explanation, animal hoarders can create some truly shocking situations, as the following photos show.

Credit: Bradley J. Boner/The HSUS