As for rights, in an owned situation, a slave has any and all rights that his/her master gives him/her. To assert that no slave has rights, isn't in keeping with reality. You have whatever rights your master deems that you have. In some relationships you may have quite a few rights.

As for slaves historically, with the exception of the african slave trade, in situations such as ancient Greek and Roman slavery, slaves did have certain rights.

However, I think a discussion of "rights" is pretty pointless because I think all rights for all people are always theoretical. As a citizen of the United States, I have the right to be free. If I am locked in a cage, my right has no bearing on my reality.

All I consider valid are will, opportunity, and action. If I have the will to do something, and the opportunity to do something (and I understand and accept the risks), I will do it.

Owned property or not.