The New Jersey Society for the Prevention of Cruelty to Animals says the cats were taken after the execution of a search warrant Thursday at the Hunterdon Humane Animal Shelter in Alexandria Township.
The SPCA says the cats were being improperly sheltered and all needed emergency veterinary care. Spokesman Matt Stanton says four were in such poor condition they needed to be euthanized.
Stanton says the cats were being kept in dirty, crowded conditions.
The Hunterdon Humane Animal Shelter is run by a nonprofit group. The shelter's director was not available for comment.
The SPCA says charges are pending.
Two pigs were also found in poor condition at the shelter and are awaiting inspection.