Conducting an appraisal of published literature, researchers sought to assess evidence of the impact of cat group size on cat well-being in domestic homes. The appraisal results highlight the complex, multifactorial relationships between cat well-being and various social and environmental factors. These may be as important than the numbers of cats living in a household.
Source: Journal of Feline Medicine and Surgery, February 2022. Link.
Also see: A new cat at home, Meow Foundation. Link. Tips for integrating a new cat.