We really try to do nose to tail use of all our animals. When the pigs are slaughtered here on farm, we make soup stock from the heads. Ken has an outdoor soup kettle he heats with wood. After a while we pull the bones and I pick the meat - just like that turkey soup after Thanksgiving, then return the bones and continue simmering to break down the marrow and cartilage so it is part of the stock. Ken also adds vegetable culls for more depth of flavor and minerals.
Then we remove the bones. Ken strains the stock , we let it cool, skim the fat and then I pressure can most of it for future use. This year I did two batches of 20 pints and have an additional gallon we are using now.
Once the meat comes back from the locker we render the lard. Animal fat was said to cause heart problems. Now we are reading that the real culprit is hydrogenated fat. Animal fat is only as good as how the animal was raised. An animal with access to the outdoors will have Vitamins A, D, E and K in the fat. Also consider that toxins ingested by animals are stored in the fat. It is imperative to obtain fat from animals exposed to as few toxins as possible - clean water and feed without pesticides.
We both like cooking with lard as a little goes a long way and it can take heat. I love olive oil for salad, but for cooking and baking, give me lard!