Mountains of pig dust at the Stockyards, 1930, Chicago. For scale, notice the man standing in the center of the photo.
The caption read:
“In mammoth dust heaps ends the pig. Completely disassembled, his remains ground to pungent dust, he fulfils his final function as good food for animals. In this Swift storeroom are 1500 tons of rich pig dust, macabre mountains of meal.”