These are the pupae of the superworm darkling beetle (Zophobas morio) being raised to be food animals for birds and reptiles. These ones have missed being fed out, and are busily changing into large beetles. Then they'll breed, produce eggs, and their babies will feed the babies of birds and reptiles.
I have yet another new (used) camera so the settings for this photo are particularly weird. I'm gonna call it part of the zoo horror movie why not.