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While spaying is traditionally recommended for kitties between 4 and 6 months of age, spaying as young as 8 weeks old is considered safe, according to Cat Channel. Many animal shelters actually spay kitties prior to adopting them out at this age.
Feral kittens over 8 weeks of age can be safely spayed or neutered as long as they weigh at least 2 pounds. We recommend that unsocialized kittens over 8 weeks of age be trapped, neutered, vaccinated and returned to the colony.