Shelter cats are happier, more playful, friendlier with each other, and less stressed when they have more room — 4 square meters, or 43 square feet, per cat, to be precise.
In a study published in the June 2016 issue of Applied Animal Behaviour Science, Swedish researchers tested the play, mutual grooming, and inter-cat aggressiveness of cats given various amounts of floor space in an animal shelter.
Among their findings (paragraph breaks added to improve readability):
The difference in available space had an effect on solitary play, which increased significantly when increasing the area from one to four square meters per cat. This difference could only be seen in the afternoon, just before the cats were fed. Play could be an indicator of positive welfare (Sarti Oliviera et al., 2010) and has been shown to be suppressed in cats experiencing stress (Carlstead et al., 1993).
Therefore, we believe that this result gives an indication that larger areas could increase the welfare of cats in groups. We also found that cats licked each other more often, had more body contact and were more active, i.e. changed resources, when they were housed in the largest area compared to the second largest area. One interpretation of the increase in friendly social behaviour with larger space could be that the cats had the possibility to choose when and whom to have social contact with. In a smaller area with the same group size, i.e. at a higher stocking density, they are forced to have shorter distance to other individuals.
Two components that are essential to reduce stress is the possibility to choose activity and behaviour, and to control the environment (Weiss, 1971). If the cats perceived that they had more control and more choice in the larger space, this would increase the welfare of the cats in this space as compared to more crowded environments.
You can read the abstract, and purchase the full study if you are not a subscriber to the journal, at the link below.
Loberg, Jenny M. et al., The effect of space on behaviour in large groups of domestic cats kept indoors, Applied Animal Behaviour Science , Volume 182 , 23 – 29