The main problem with pig ears and rawhides, if they get a chunk off, or try to swallow it before its small enough, they can get stuck in the throat or intestine and can't digest,which often leads to be breeding ground for bacteria that can make them really sick. No chew is 100% safe, but safer choices are raw meaty bones and/or bully sticks (100% digestible as it is muscle and not the skin [rawhide]). Even if they do end up getting a bigger piece down, it will digest and is less likely to get caught in the throat or intestines. ANY chew can be harmful, for myself personally there are some that just aren't worth the increased risks they may pose. I also don't feed greenies, but many do without incident, I just choose not to. I only give mine bully sticks or the inedible nylabones. I also watch for any signs of breakage or damage and remove them if needed.