Tracking Animals Since most American farmers are accustomed to keeping their pigs in stalls, they are used to knowing just where to find them. They enter a barn, walk down the aisles, and check on their animals all lined up in a row. The data for each pig is on paperwork attached right to the front of her stall. If a sow needs a shot or a pregnancy test, she is immobile and can be easily checked on later. Furthermore, because sows are assigned stalls in the order they are moved into the room, the staff can quickly pinpoint groups of pigs that are all at the same stage. Like, a set of pregnant sows who are all reaching the end of their pregnancies. In a large pen system, farmers needs help tracking down individual sows and giving them personalized care. Electronic record keeping systems, where sows are given scannable ID tags, are the most efficient way to do so. This allows the farmer to walk through the herd with a handheld device that lets him pull up and edit the data for individual animals. The records are also accessible via desktop computer, where a variety of useful reports can be run. In very large pens, like nested gestation pens, Electronic Sow Feeding stations are used. These have the ability to automatically sort out animals, when they meet specified criteria. For example, a farmer might program in the IDs of a sows close to giving birth. The next time she enters the ESF station to eat, the exit gate will shift and she will exit into a waiting area, where the farmer can walk her to her farrowing pen. This technology enables the farmers to work closely with their animals and get to know them well, but it's a big change and requires the farmer to be open to changing the way he or she manages and interacts with pigs.		When pigs are restrained in crates and stalls, cards above their stalls record their information and make them easy to locate.   In a large pen model, farmers can move freely among the animals, but require technology to locate and manage individual animals.