Why keep slaves?

[DogFromDuckhunt]

Good points but in a world of limited resources I think you'd need more motivation than sex and entertainment.

Depends. Knew an accountant who worked in the corrections department and remember her saying something about prisons having stockpiles of food, materials, etc. Could be the Mallers weren't thinking that far ahead considering what they had on hand.

Was either Latch or Durai who said they wanted to send some people to the Tower. Might be they took in more than they could handle and now they're trying to adjust.

I doubt a slave would be trusted to forage but it would explain the runaways.

Don't see why not though. Might not be the best situation and you might take some beatings, but at least they're living.