I'm sorry for your loss.i like these pellets due to them being grain free,also cold pressed so the original nutrients remain without adding as not heat treated.so do not swell in the digested tract and easier to digest.i believe the best thing is not to give anymore than one table spoon of pellets for each guinea pigs.i go to a vet who is exotic ,he believes alot of the stone issue is genetic in orientation,you can only do what is recommended on the forum for bladder piggies,reduce the risk ,but not eliminate the risk.ive luckly only had one piggie with a stone,she was 3 when i adopted her,therefore many already been at risk prior to me adopting her.maybe someone can link the diet for bladder piggies.Ellie is very good,ive been to her for other issues.maybe research cold pressed pellets to get an unbiased review.