According to Nature's Variety's website, Instinct
has made alterations to all of its kibble formulas. None of their top 6 ingredients have changed, however some formulas have dropped up to 3% off their protein and/or fat levels. Minor changes to vitamins, minerals, and botanicals have also been made. I've also added in their rawboost rabbit formula.
Unfortunately, this change has bumped Instinct Chicken formulas out of the green tier. As I have stated on the ferret food chart page, however, Instinct Chicken kind of an outlier that is scoring lower than it really should because it has such limited ingredient variety. In my opinion it belongs in the green tier, but since the site uses a mathematical formula to score food itself, I can't put it there manually.
Overall the benefits of scoring food mathematically (less bias, more transparent, easier to update, etc.) far outweigh the flaws, but there will occasionally be the odd problem like this.
Additionally I'm systematically working through a chunk of the foods that haven't been checked for updates in a while. These are the ones that have had formula changes in the past year or two so far: