Re-homing is not the same as relocating. You probably didn't do the opossums any favors. Now they have to try and find water and food. Plus they may all be killed anyways since you just drooped them off in another animals territory. In California it is illegal to trap and relocate. We have opossum, raccoon, skunk, bear, coyotes, fox, rats, mountain lion, stupid neighbor's free to roam cats (most don't make it out of the yard, I have 3 dogs), snakes, and who knows what else I haven't seen. We don't have many stray dogs, but fences do break so it's always a possibility. I don't bother things in their own environment, but I have not only the right to protect my family and livestock but also the responsibility. Do you not know that many of these are carriers of rabies? Good luck, I hope you find something that is more humane (including quick death) and legal that will work for you. Building fort knox is sometimes an ongoing learning process.