I'm going to try charring bones to see if I can get them to the point they are easy to crush. I'm not sure if I can just add some to wood that I am charring or not? Seems like it might take bone a lot longer to char but I haven't tried it yet.
I've had excellent results adding chicken, quail and rabbit bones to my compost piles. I've found they break down pretty quickly with thermophilic composting, though the rabbit skulls usually took two turns in the piles.
I also usually add vinegar to my pot when making broth, which helps soften the bones somewhat, but I probably only use half the bones that way before composting.
A piece of land is worth as much as the person farming it.
-Le Livre du Colon, 1902
I char bones along with other stuff inside an old steel toolbox.
They crumble nicely when done.
When I pressure cook the bones, they crumble,if not on the first pass, then on the second.
Fresh, uncooked bones seem not to be splintery.
I throw rat corpses into the back bed, something, maybe the chickens, makes them go away.
I think lye will quickly decompose bones, be careful if you try it.
Wood chipper would be my vote for buying an actual machine for the job.
We can be certain it will get the job done, and it has other uses.