Social compatibility between cats in multi-cat households is the foundation of good welfare, with incompatible groups causing chronic stress that undermines all other welfare provisions.
Multi-cat household welfare is fundamentally about social compatibility, which cannot be achieved through resource provision alone. A subordinate cat in an incompatible household may have access to adequate food, water, and litter boxes but live in chronic anxiety from the threat of dominant cat aggression or blocking. This is invisible welfare harm — the cat does not appear dramatically unwell but experiences sustained psychological stress that manifests in health problems and reduced quality of life. The welfare obligation is to honestly assess compatibility and take action, including potential rehoming of incompatible cats, rather than assuming that adequate physical resources solve social welfare problems.