You have to remember that dogs are more tolerant of bacteria, etc than people are; after all, consider their natural wild eating habits (not just hunting, but consuming partially spoiled carcasses, etc.) Now, I never feed my dogs anything like raw chicken, or spoiled hamburger, etc, but I don't think that letting them swallow bits of plastic chew toys can possibly be good for them (why are they called 'nyla' bones--they are made of nylon plastic, mostly, right? I have only had one of these for my first pup, and she didn't like it one bit, so have never bought another and don't really remember). In my opinion, which you guys are free to disagree with, just don't be too hard on me, lol , I would rather risk the bacteria (in rawhide) that they would be exposed to if they chose their own diet than feed them plastic that could get stuck in their GI tract and cause blockages, etc.