Keeping animals in groups of 100 or more has the potential of reducing housing costs (i.e. – penning) and giving producers more flexibility in building design and management. Managing pigs in large groups of 100 or more will result in a reduction of average daily gain, usually during the first 2 to 4 weeks after the group is formed. This is the only area that needs improvement because other aspects of productivity show little or no difference between large and small groups. Any loss in productivity appears to be small and is compensated for by facility costs and flexibility of management. Aggression is lowered in large groups because pigs tend to develop a tolerance to strange pigs. These animals may even adapt better to group housing systems in the breeding herd. Producers should not redesign partial-slat floors from small to large group housing as this may lead to poor dunging patterns. Surprisingly, investigation of animals and feeders takes less time in large group pens than small group pens. Treating them is easier than one may think because the pigs are more approachable in large groups. Hallways need to be larger and doorways need to be wider for large groups to move through. Automatic or electronic sorters are useful in replacing manual sorting of pigs. Scales are set up at the entrance to a feeding area and pigs move through the scale and are sorted to a light or a heavy side. Continuous sorting is the better method as it is less stressful for the pigs and requires less labour. Pigs need to be trained in order to adapt to this system though. The use of these automatic sorters can be useful for incorporating new management possibilities such as phase feeding and grid sensitive marketing.