"Where is there something to challenge?"
if animals are legally viewed as property, once you take possession of them they are YOUR property. The only legal recourse to remove them is due to suspected abuse or neglect.
That is how they are unenforceable. Once you relinquish the property you have no more claim to that property. Period.
-Politics is like driving. To go backward, put it in R. To go forward, put it in D.