In addition, the review summarizes the related literature and points out limitations to open up new dimensions for future researchers to explore. This review describes the state of the art in 3D imaging systems (i.e., depth sensors and time-of-flight cameras), along with 2D cameras, for effectively identifying pig behaviors, and presents automated approaches for monitoring and investigating pigs’ feeding, drinking, lying, locomotion, aggressive, and reproductive behaviors. However, the lack of targeted information about the application of cameras in the pig industry is a shortcoming for swine farmers and researchers. Cameras have ample chance to monitor pigs with high precision at an affordable cost. On the other hand, camera sensors are cheap, commonly available, and easily used to collect information compared to other sensor systems in precision pig farming.
Some data collection techniques in PLF such as RFID are accurate but not affordable for small- and medium-sized farms. The preeminent purpose of precision livestock farming (PLF) is to provide affordable and straightforward solutions to severe problems with certainty.
