My past rats have lived perfectly healthy lives using Kaytee blocks in their diet. No tumors. No cancer. Thanks. By the way, they have recently reforumulated their pet blocks. Are you seriously comparing feeding this to "Rats can eat trash" guy?Now YOU stop right there. Kaytee's Rat Blocks should NEVER be used. They have like ash or something that can cause tumors or cancer in rats. Stick with Mazuri or anything that ISN'T Kaytee.