Please don't think negative on all hunters for these inconsiderate few. I, like others, always pick up shells and trash as I go. But then, I'm only hunting on land that I either own or have personal permission to hunt.
If you are finding shells from hunters on your land, did you give them permission? If so, you should know who they are and can ask them to pick up after themselves.
If not....
If you are finding shells from hunters on your land, did you give them permission? If so, you should know who they are and can ask them to pick up after themselves.
If not....