ok replying to my own post, but I really think you need to call your local animal control service. There are laws, that were broken, if you call them and have them and open a case, it would really, make a case, for your stance. That way future parents, know not to mess with you : )
And don't be too discouraged, you did a good thing, all your other chicks are doing good, Just take this as a learning experince. I'd really look into making a "contract" for the next batch of chicks you adopt out. : )