Visiting a slaughterhouse or farm can be beneficial in several subjects, but it's important to note that students should be of legal age or have written consent from their parents or guardians. Furthermore, not everyone is prepared to witness the realities of a slaughterhouse firsthand, so students should be informed beforehand about what to expect.
In this case, the teacher called the slaughterhouse to inform them that a class project was going to be done to learn about the processes prior to the sale of the meat.
Since video editing requires computer skills, this activity can be carried out in a Computer Science course. However, there are also other areas, such as Economics, where it is common for students to be asked to visit local private companies as an assignment to learn about their operations.