Yep,Harley took a square rawhide, and chewed it into a perfect circle every single time! I told the veterinarian that something was wrong months before he died. Had she listened to me, he would have lived. No matter how I insisted though, she told me I was wrong.
$4,500, ten days and even giving him plasma didn't save him. He passed on Thanksgiving morning 2010. So much drama involved.
For those that don't know, there is nothing wrong with rawhides. The problem is when the dog swallows big chunks. The rawhide begins to pile up, and block their intestines.

I had a mastiff that just dropped dead on me - she was only 11 months old.

And, she was the dog that replaced my bulldog that died of cancer, right before his second birthday. I had a strain of bad luck with dogs for a few years. Cancers, strokes, neurological problems. It's why I don't have mastiffs anymore. I couldn't handle it.