Multi-cat households create chronic social stress for many cats due to competition for resources, territorial conflict, and incompatible personalities, with significant welfare consequences.
Chronic social stress in multi-cat households causes immunosuppression, idiopathic cystitis, and behavioural welfare problems including indoor marking and redirected aggression. Resource guarding prevents subordinate cats from accessing food, water, and litter boxes. Environmental modification to provide multiple separate resource stations significantly reduces inter-cat stress.