Rules of the Farm
There are two rules everybody knows: no antibiotics, ever, and your shit doesn't belong to you. Those aren't the only rules, but they are the ones that define the life of a microbiota farmer. Your shit is where the bioengineered bacteria that lives in your gut is harvested from: the delicate microorganisms must be grown inside a human before transplanted into the much richer humans that will benefit from them.
It's not bad, as jobs go, if you don't mind eating what you're given, exercising when you are told, taking whatever they give or inject into you, and never leaving the compounds everybody calls the Shit Farms even when being paid not to. (They used to use prisons until stopped by the political backlash against treating prisoners well enough that their gut flora would be useful; it wasn't good for branding anyway. The long recession, in any case, had made cheap labor a non-issue.)
There are three other rules you learn once you're inside, with varying degrees of explicitness and threat: You never ask what they are growing inside you. If your body starts doing something it never had before —if your senses change, if your thoughts are new, if there's pain or pleasure or something you don't have a word for— you report it promptly and endure it quietly. And you don't complain if blood samples become frequent beyond the needs of analysis or if you wake up after anesthesia with something hurting in your head's bones and a bad dream's non-memory of a distant sucking sound.