Here's what led to the revelation:

Last spring we had 2 hogs butchered that hubby raised (not at our house). I had the butcher save everything which included the heads split in half. So today I decided to make bone broth with one. I unwrapped it and started getting a little squeamish, it barely fit into my stock pot. I had to decide did I want the eyeball facing up or the teeth? I chose the teeth, the snout is pressing on the glass lid. I'm not sure I can go through with this. I put it to cook on my parabolic solar cooker figuring that it would cook down some before I had to bring it in for the night, at which time the bones may be soft enough to smash the snout down so it's not pressing against the lid.

I was a chef for years, I have no problem cutting up meat, but I never worked with an animal head, seeing the teeth and eye is disquieting.