How were the slaves confined in an inhumane manner

I am assuming you want a an answer from a specific book, as to how, so read the book and find out.

In real life and in history there were many ways, first just being slaves, no freedom to go, children taken away, families sold apart. Poor sanitation.

But then on the other hand, they were valued property worth a lot of money, a owner would not do something to risk losing the investment he had in the slaves,