(i) Spatial organisation was studied in small flocks of domestic fowl to elucidate its underlying mechanisms and provide a basis for future comparative analyses. (ii) Approach-tolerance distance values were obtained in a non-competitive feeding and a roosting situation. (iii) A zone of variable width across which the likelihood of approach eliciting agonistic response increased centripetally was observed around feeding birds. No sexual difference in zone width was noted, and tolerance of approach was great. (iv) No indication of constant Individual Distance in roosting birds was obtained, though spatial adjustment following agonistic interaction was observed. Clumping was common. (v) Activity-dependent variability in spatial organisation was described and correlated with the distribution of aggressive behaviour. (vi) It was postulated that the state of dispersion during specific activities was explicable in terms of the interaction of the opposed tendencies to congregate and aggregate and to react aggressively when approached. (vii) The nature and distribution of clumping and allopreening responses were described, and their causation and function discussed.