I'm pretty sure the bone scraps have already been distilled and all the liquids are long gone. Bone char is used to filter many things, including making sugar white.
Interesting. The first thing that pops in my mind is the horrible smell when the dentist is grinding a tooth for a filling.
The other thought I had was if there are deer bones in the mix the possibility of moving the prions that carry cwd into the atmosphere.
Just my random thoughts out loud