Freedom's Landing by Anne McCaffrey - USED

But on the whole she has survived rather well. The Catteni value strength and intelligence in their slaves. And so Kris has found herself part of a tremendous alien experiment - one that gives her back her freedom, in a way, though she knows she will not see Denver again. Once again she was driven into the hold of an enormous ship, and once again awoke on a strange planet, this time with no master giving orders. The Catteni have discovered a new world, and they have a pragmatic way of finding out whether it is habitable: hundreds of slaves have been dropped there and left to their own resources. If they survive, the world will be deemed fit for Catteni colonization. If they die, well, slaves are a nuisance to replace, but there are always more.