There are many different earthworms in this world.  I plan on updating this page very soon to help you identify the right worm for your bin so that you will be successful.
Meanwhile please note that there are invasive species which do more harm than good.
The Wisconsin DNR is working hard for all of us to understand the potential damage of the Jumping Worm or Amynthas  here is their website dnr.wi.gov/topic/Invasives/fact/jumpingworm/index.html