Figure 2.

Sow lactation feeders, feeder trigger, and adjustment mechanisms. For feeder adjustment, the PVC tubes were pushed against the feeder wall by a screw to maintain the gap between the end of the PVC tube and the bottom of the feeder bowl with friction. The Rotecna and SowMax feeders had quick adjustment handles to control the amount of feed dropped (gap size) for each trigger by the sows. For the trigger mechanism, Rotecna has a ball structure that can be pushed up from all directions and opens a gap to allow feed to drop. SowMax has a rod that can be pushed sideways and opens a gap on the sides of the hopper to allow feed to drop.