There used to be a commercial worm system (maybe there still is?) that was a series of conveyors that moved very slowly. Food and bedding were added to one end, and by the time it traveled to the other end, the worms had eaten it all, and moved on to the newer food. The problem with this system was that if you were going to feed very much food to the worms at one time, you needed to have a LOT of conveyors.

After doing some digging, it appears that the prototype system was called the Worm Gin. The prototype was abandoned, but the company that built it still exists under the name Terracycle.