The goal of this trick is to be able to make that some individual dispensers do not deliver feed when they are all full.

When the cable moves in the direction of the arrow, the eye bolt will act as a stopper and will pull the lever that delivers the feed from the dispenser

The dispensers’ cables are connected to the general feeding cable through a hook. When we wish that a dispenser that is full does not deliver feed, we will unfasten the hook from the general feeding cable, and when we pull the cable the dispenser will not empty itself.

The general cable has an eye bolt that acts as a stopper. The dispenser has a hook fastened to the cable. This hook allows for an easy disconnection.
Explanation
Sometimes, we may be interested on a certain dispenser not delivering feed because its corresponding crate is empty. The sow may have died, or maybe we had to remove her unexpectedly due to a return to oestrus or an abortion, etc. Sometimes we may even change sow batches from one location to a different one and forget to close their dispensers, that end up becoming full.
Normally, the dispensers’ cables are connected to the general feeding cable permanently, and once a dispenser is full it is inevitable for it to deliver its feed when we provide the following meal in the unit.

Detail of a dispenser that is full but that we have unhooked so it does not deliver feed.
This farm has solved this very easily. The dispensers’ cables have a hook on one of their ends, and this hook may be fastened to the general feeding cable or not. On the general cable there are eye bolts that will act as stoppers and that will pull each of the hooks when we activate the feeding lever.

Photograph of the gestation line in which we see most of the dispensers ready to deliver feed.
PORCISO, S.L. farm - Soria (Spain)