The objective of this investigation was to determine the impact of group size and age on the perching behaviour of young domestic fowl kept under indoor housing conditions with equal resource availability across group sizes. White Leghorn pullets were reared in groups 15, 30, 60 and 120 at a constant density of 5 birds/m2. Each pen contained perches 20, 40 and 60 cm above the ground. Perch space per bird per perch level was the same for all groups. The proportion of 3- to 18-week-old birds roosting on perches during scans throughout the photoperiod decreased with increasing group size, from 41 A