To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
These do not last long with my Amazon parrot, but he sure likes tearing them up! So, I guess I may continue to use these in making shredding toys for him, I just need to figure out how to be more creative with them as my Amazon is not much a foot-toy kinda bird.