Dude, fingernails, hair, blood, etc. can get in food no matter WHAT restaurant. I work in a classy restaurant. Shit happens. Because ONE kidney got in ONE meal served in ONE KFC of the hundreds there are, you'll stop eating there?
I personally think that's a pretty good track record, actually. Also, kidneys are actually edible if you cook them right. Now yes, this is pretty nasty, but again, when you're in the food industry, shit happens. I would avoid that particular KFC because it sounds like somebody dropped the ball, but otherwise, I won't avoid it. I don't eat there often anyway.