in order to eat the way our ancestors did, and reacquire our health and strength... we need to get over being squeamish about these things.
It is only over the last 3 or 4 generations that things have changed... with the exception of some cultures, and people who refuse to give up what they know works.
Several markets in town cater to any number of traditional ethnic diets... chicken feet, pork heads, feet, you name it... one of them, in addition to the above mentioned items, has a whole wall of huge fish tanks with live fish... lobster, crabs, you name it... you pick it out, and they butcher it right there... you want the offal, bones... they are yours.