Multi-cat households create welfare challenges as cats are not naturally social animals, and resource competition causes chronic stress in many households even when no overt fighting occurs.
Cats in competitive multi-cat households experience chronic low-grade stress from resource competition, social monitoring and inability to fully relax in shared spaces. Passive intimidation — blocking access to food, water and litter — causes stress without visible aggression. Chronic stress suppresses immune function and predisposes cats to idiopathic cystitis and behavioural problems. Most multi-cat household problems are amenable to resource addition and spatial management.