Companion Animal Resources
American Society for the Prevention of Cruelty to Animals
Animal Defenders International
Animals in Mind (behavior training)
Humane Society of the United States
Korea Animal Protection Society
United Animal Nations/Emergency Animal Rescue Service
Specifically Animal Hoarding
Animal Hoarders: Behavior, Consequences, and Appropriate Official Response
(may take awhile to load)
Animal
Hoarding: An In-depth Look at the Phenomenon
(The) Hoarding of Animals Research Consortium (most comprehensive and most cited elsewhere)
Specifically Puppy Mills
Specifically Spay/Neuter Resources
Operation Stop Pet Overpopulation Today
Spay-Neuter Assistance Program