Interpret the statement "...they use everything of the pig except the squeal."

This means that EVERY part of the pig is used by the meat industry. NOTHING is left out.... not the hooves, the snout, the intestines..... not anything.

Text evidence:

For it was the custom, as they found, whenever meat was so spoiled that it could not be used for anything else, either to can it or else to chop it up into sausage."