more than likely the fish were in a more negative mood, going for the struggling minnow over the less lifelike pieces of minnow that you were jigging. when that happens, if you don't want to just set up multiple dead rods with minnows, downsize to a smaller jig and tip it with spikes or a waxworm.
as for your poor hookup ratio on the dead rod, check to make sure your hook point is sharp, and possibly upsize your hook.