Just out of curiosity, is there any kind of legal deal where a taxidermist with a lot of unclaimed mounts could make the effort(s) to contact the owner - either via phone or registered mail - with x-amount of time to retrieve it, and if it's not retrieved it would be discarded?

One of the dry cleaners we previously used had something like that: "Clothing not picked up after 30 (or 60?) days will be discarded." I guess they either sold it and wrote it off or donated it perhaps for a tax break. But they couldn't keep everyone's chit hanging around in their tiny shop.