Hmmm...that is in the buiscuits...

But does anyone know how much proof or research has been done to base a fact that it is bad for rats/mice?

Icarus doesn't seem to have anything wrong with him...Just Frisco...He's not itching anymore, I gave him a good wipe-down with baby wipes, got all the blood off of him (he scratched himself to that point ), and the only thing that is weird now is that he's bloated...