Gestation stalls or individual stalls were first introduced in the 1960s as a way to help protect and nurture all sows (female pigs) during pregnancy, a time when they are particularly vulnerable. On larger farms, the crates are used to separate the sows in order to keep them from fighting and injuring each other. Using gestation crates, a farmer can individually monitor how much each sow is eating and adjust the amount of feed she gets per day so that she is in proper condition prior to farrowing. Peer reviewed research has shown that this system allows for optimum animal safety and health for pregnant sows. However, it is important to note that there is no one right system for this process and both group housing and individual stalls have pros and cons.