"Unwanted kittens" refers to kittens that are not desired or needed by their owners or caregivers. They are often born to cats that have not been spayed or neutered and are then left without a loving home. Full definition
All of my pets, two dogs and five cats, are all spayed or neutered so they are not producing litters of unwanted kittens and puppies. (hswaynepets.org)
A female kitten needs to be spayed as early as four to five months of age to prevent unwanted kittens. (petsmagazine.com.sg)
And you will prevent the births of more unwanted kittens and puppies. (homevet.com)