Five methods for estimating the stocking density of sheep confined in a pen were assessed. The pen (2-35 m × 3-01 m) simulated the pens on a normal road transporter. The trial used 50 lambs (average weight 34 kg) of mixed sex and breed, held at five stocking densities - 0-466 to 0-824 m2/100 kg or 214 to 121 kg/m2 covering the range used in commercial practice, and 14 assessors, all experienced in handling animals. The best method was that based on the girth measurement of a sample of animals to estimate liveweight and a count of the animals in the pen. The methods based on using a moveable gate to take up free floor space, assessing the difficulty of moving through the pen of animals, using photographic scales, and counting the numbers of sheep across transects were generally less successful.