Well, gee, I started to edit a lengthy disagreement with Noweia... I intended to discuss the fact that while parasites are always a possibility, the fact is wild dogs, coyotes (herein the western U.S.), fox, wolves (recently reintroduced to the wild here) as well as feral cats seem to have very little problem with them. I was going to say that if you let Fluffy the cat or Boopsy the in-bred, high strung, yappy minature whatever outside and they encountered a ripe road kill whatsit, they would first, roll in it and then eat some of it and then bury the rest, returning, if able, later to dig it up and devour the remainder. I was also going to expound on the contents of commercial pet foods, including that BHA, BHT and ethoxyquin that are found in many pet foods... but I thought better of it and simply enclose this quote from William Pollak D.V.M. :
"Dogs, cats and other animals live for years on foods that come out of bags, cans and boxes. But do these foods promote health? If they did, our companion animals would enjoy long, happy lives free of arthritis, hip dysplasia, eye problems, ear problems, fleas and other parasites, gum disease, lick granulomas, thyroid imbalances, skin and coat problems, personality disorders, birth defects, breeding problems, diabetes, cancer and other major and minor illnesses. Before World War II, most North Americans fed their pets raw bones and table scraps. Today, everyone uses convenience foods, and pet food companies are industry giants. Diet isn't the only thing that has changed. So has life expectancy, with the life span of many breeds now less than half what it was two or three decades ago. Skin and coat problems are so common that we accept them as unavoidable, and today's vets routinely treat conditions that used to be unusual or even rare."