Bests & Worsts Reviews from Amazon

I have been feeding my two 1.5 year old cats this product for the last year or so. Initially, I had no problems with it because my girls loved the flavor and I thought it was helping with one of my cats sensitive digestive system. A few weeks ago, she started having problems again without any change in her diet, so I did an online search on whether Natural Balance changed its formula. I couldn't find anything on that but I did find a bunch of disturbing images of stones and pebbles in their products that customers found as well as reviews of pet owners who reported a decline in their cats' health due to this product. I was concerned but my vet told me he wasn't aware of any issues with Natural Balance. Then today I found 2 pieces of rocks in my cats' canned food (see image). What is disturbing is that I've seen it before in their food but I thought it was supposed to be part of it and didn't inspect it further. I wish I had researched this product more extensively prior to placing my cats on this diet. I will no longer buy products from Natural Balance and I will likely have my vet runs tests on my cats to make sure this didn't cause permanent damage to them.