As producers improve their reproductive herd performance with both genetics and management, the number of pigs weaned per litter and per week increases. At the same time, slaughter weights are increasing. Combined, these improvements mean too many pigs in the facility and other issues related to pig flow in facilities become a bigger concern. One option to deal with more weaned pigs is to fill a room at weaning to a fixed capacity, with the excess pigs beginning to fill the next nursery room. The challenge in this is that heating and ventilation systems are not designed for partial room fills. A second challenge to this option is that the number of days available for nursery pig growth decline. This creates tremendous stress on the grow-finish rooms since the pigs are now close to 3 kg (6.6 lb) lighter at placement into these rooms. To make this option work, the producer needs to add at least 1 more nursery and/or finishing room. This comes at a huge price since the number of days pens/rooms are not stocked with pigs increases in the system, adding to the capital expense of production. An option that some producers are using is to modify pig flow by going from a weekly farrowing system to a batch farrowing system. That is, instead of farrowing 30 sows every week, they are farrowing 120 sows once every 4 weeks. They accomplish this by breeding for a 2 week period with a 2 week non-breeding period. This keeps weaning age of pigs within a batch fairly close (within 2 weeks) and allows for a large number of pigs to flow through the system at one time (approximately1100 pigs every 4 weeks). Larger groups of pigs also solve the problems of small pig numbers in one or more rooms since there are larger numbers of pigs available for allocation across a number of rooms. One challenge in this scenario is the limit of 6 weeks of nursery capacity (6 rooms) when farrowing occurs every 4 weeks. The solution is to add 2 nursery rooms so that nursery capacity matches farrowing capacity. There then is 8 weeks of nursery capacity, with the pigs remaining in the nursery for 52 days before relocation to growing-finishing rooms. This often means the pigs are 7+ kg (15+ lb) heavier at placement into the growing-finishing phase of production, which results in more opportunities for the pigs to achieve the desired sale weights prior to the need for the space for the next group of nursery pigs. A second challenge is the altered labor intensity in the breeding/gestation and farrowing facility. With batch farrowing, instead of weekly matings, farrowings, weanings, everything is concentrated in a 2 week period with the other 2 weeks having a relatively light labor demand. With the recent approval for dietary inclusion of ractopamine (Paylean®, Elanco Animal Health, Indianapolis, IN) in finishing diets in Canada, growers in both the US and Canada can now use this product to improve daily gain and carcass lean. While use of Paylean® in late finishing diets will improve pig flow from finishing rooms, it doesn’t solve space issues associated with overcrowding in the nursery. Pig flow problems can become very real as the industrymakes genetic and management progress. While all-in/all-out pig flow is desired for maximizing pig health and minimizing disease transfer between multiple ages of pigs in a production system, the reality is that space becomes a very real limit to performance as productivity increases. Future investments in facilities must include consideration of pig flow options so that improvements in reproductive performance and/or further increases in sale weight can be accommodated more readily than is possible with current fixed flow systems.