Multi-cat households can be sources of chronic stress for cats when social, territorial, and resource needs are not adequately managed.
Chronic social stress in multi-cat households causes genuine suffering through anxiety, suppressed immune function, and the pain of FIC episodes. Cats that live in constant low-level conflict are in a perpetual state of stress that owners may not recognize as harmful. The absence of overt fighting does not mean cats are socially compatible - passive intimidation and resource guarding cause equally significant stress. When the number of cats in a household exceeds what can be managed for the welfare of all individuals, the welfare of each cat is compromised. Responsible ownership includes honest assessment of household capacity.