Drag Feeder chains require a little bit of slack on the return side to operate most efficiently. To adjust the chain, first de-energize the feeder and follow all lockout/tagout/blockout procedures to ensure no energy can get to the machine while making the chain adjustment.
Position the hand pump on the tail side to extend and pump oil into the cylinder to relieve pressure off the shims. Insert shims to lock the cylinder in place. Position the hand pump to neutral and repeat for the cylinder on the other side of the feeder, ensuring to add the same number of shims to each side. lel from the head shaft through the tail shaft. (no idea what this means)
Watch this video for step-by-step instructions on how to adjust chain tension on a Drag Feeder.