Two states specifically target animal "hoarding" in their laws.
Under Illinois law, 510 ILCS 70/2.10, "Companion animal hoarder" is defined to mean "a person who (i) possesses a large number of companion animals; (ii) fails to or is unable to provide [humane care for animals as required by law, 510 ILCS 70/3]; (iii) keeps the companion animals in a severely overcrowded environment; and (iv) displays an inability to recognize or understand the nature of or has a reckless disregard for the conditions under which the companion animals are living and the deleterious impact they have on the companion animals’ and owner’s health and well-being."
If a person found in violation of the state Humane Care for Animals Act is determined to be a companion animal hoarder, the court must order the convicted person to undergo a psychological or psychiatric evaluation and to undergo treatment that the court determines to be appropriate after due consideration of the evaluation. 510 ILCS 70.3 – 3.02.
A 2008 Hawaii law, HRS § 711-1109.6, makes it a misdemeanor if a person with 15 or more dogs and cats fails to provide "necessary sustenance for each dog or cat"; and fails "to correct the conditions under which the dogs or cats are living, where conditions injurious to the dogs’, cats’, or owner’s health and well-being result from the person’s failure to provide necessary sustenance." The mental state of the hoarder is not an issue under the Hawaii law.