The poem is a short, fragmented sequence of images, and it doesn't hand over a clear story. It begins with prisoners made to eat the worst of the meat, "skin / and monstrous fat," a picture of degradation that is physical and hard to look away from. Then it shifts. Someone kisses a "flung stone," and the stone is "raw as their opinions of sin." That comparison links the roughness of the stone to the harsh, unfinished judgments people hold about right and wrong.
The last two lines drift into wishes or fantasies: "a fancy woman" and "more sleep." These read like the things a prisoner might long for, a little luxury, a little rest. The poem never says so outright, so that is an inference from the way the lines trail off.
The speaker stays mostly detached, simply setting images side by side. The mood is bleak and uneasy, with a small ache of longing underneath. The gaps between the lines leave the reader to connect them.