When harvesting materials from the various creatures around the World, the creature models should have parts missing.
Decapitated -> Head Removed
Skinned -> Fur/Hide Removed leaving bare flesh across the Carcass
Paws/Hooves/Feet -> Removed aswell
Bones -> The various bone pieces should open up parts of the Carcass, aka harvesting Ribs should open up the Chest and reveal Rib Fragments along the inside.
Also to harvest bones, maybe creatures need to be skinned first in order to retrieve them.
Feel free to add ideas.
Edit: It's great for those scavengers to spot from afar, knowing whether a carcass is worth running over to retrieve the scrap no one else wanted.