"Farmed"? No.

But attacking the supply side has only made the remaining poaching more profitable.

A better approach would be a certification program for ivory collected from elephants experiencing death by natural causes, including posting of DNA markers so that any given piece of ivory would be DNA-checked against the roster of legally-harvested "donors". Other ivory sales should be discouraged like with conflict diamonds. The proceeds of the legal trade could be used for habitat and protection of wild elephants and for rescue/rehabilitation of orphaned elephants.