I am trying to figure out how I avoided this. My dog joyously ANNIHILATES anything he is formally presented with, yet will not touch anything he has NOT been explicitly given. Been that way since puppyhood; I take no credit- I think I had to redirect / trade a shoe for a benebone / antler like twice. Lab Mastiff mix, otherwise dumb as a box of hammers.
Uncanny.
Now that I think about it, I need to review my split-elk-antler expenses- I may have simply bought my way out of the problem.