Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I’ve been buying these for my cat for the past 4-5 years. One of the best supermarket brands. I am glad I can now conveniently order it from Amazon and for a better price that at our local supermarket.