Diamond Maintenance 30/15 for Moderately Active Adult Cats Dry Food, 40-lb bag

Background: I have ten cats ranging from 18 years to 5 months, so when I found this food that came in such a large quantity, I was excited. My cats have been eating it for two months. The first thing I noticed was an increase in vomit and a few mild cases of diarrhea. This is common in switching foods, so I wasn't concerned and they all resolved which confirmed that it was from a food switch. However, I bought this bag in October and now it's now mid-November. During this time, I've seen a notable decrease in their coat quality (thinner, dryer, more brittle) and in the last two weeks their energy has been decreasing to the point where I was worried two of them (4 years and 1.5 years) might have gotten sick. I also noticed that those same two weighed less (my litter box has a weight feature). A few of them also began to show signs of looser and stinky stools. These are all indications that they aren't getting adequate nutrition, so I bought a bag of plain old Friskies kitten food and mixed it into their food. They have shown a notable improvement. Both of the cats who I was worried about are back to their normal energy and their coats have already started to improve. Their stools have also been normal. All of this tells me that the food doesn't meet the nutritional needs of my cats, despite its claim of AAFCO testing. If I had to guess, I would say that the vitamin and/or mineral content is not closely watched which is why just mixing in a food with higher nutrients was enough to make them feel better and why it took this long to show up. All of my cats are indoor only and the only plants I have are non-toxic. I also work from home, so I knew that none of them got into anything and both cats that felt the worse were ones who exclusively eat dry food. Thankfully, my 18 year old already gets his meals supplemented, however I noticed even he seemed to be looking more haggard. Overall, I would not recommend this food. I would caution that if you do use this food that the results may be inconsistent, and poor nutrition shows over time. If you have to use this food, like for a cat colony, then supplement it by mixing in another food. Needless to say, I've already switched mine to a different diet.