Not trying to start anything but while that it is true that pastuerized ACV is acidic and will strip the gut of beneficial bacteria the opposite is true of raw unfiltered ACV with the "mother" in it. Because it is fermented it contains the benificial flora and will help to colonize the gut...
I use the Apple Cider Vinegar (with the mother-I get Braggs) every single day. And so far (9 months, two different batches of chickens) no serious poop problems. My hubby didn't know about it and was not using the ACV while I was at work and a couple of the chicks got the runny stinky poops...