Green leaves for Mg.
For calcium, not raw but I boil bones after eating the meat. Better if with vinegar to get the calcium. You can reduce bone lelft-overs from chicken carcass to almost nothing as the bones can be almost all eaten, and marrow is very good.
I get geletine from guinea pigs bones, but the bones are really too hard for eating anything, and I have no idea the quantity of calcium that goes to the both.