I have just joined and read through all these and decided now is a good time to throw in my two cents...I have fed my cat, 4 year old JJ. Felidae platinum for about a year..he had been doing absolutely fabulous, until the past few days, when he got lethergic and weak, and today he got that hard ball in his bladder.  And began that loud meowing, notorious with bladder obstruction, thank god I was able to catch it right away and get him to the vet, but he lies in the hospital now with an IV and a catheter and in need of blood work, and will be there for 2 days...