The biggest issue with FED is jams, and this video will show one source of them and how to fix it to improve dispensing.  

The most important thing is to make sure the pellet disk is completely stable inside the hopper.  If you can wiggle it back and forth it's likely the motor is misaligned and the device may jam.  In this case, either take it apart and try to align things better, or you may even need to re-print the FED front.  See video for more info:

When everything is aligned well FED can dispense reliably.  Here is a timelapse of 1200 pellets being dispensed in a row.  Under normal conditions this would be ~1 week of continuous feeding.  I still recommend checking the FEDs and cleaning crumbs out daily if you run it over multiple days.