I think it would depend on where you got the rats. If they are clean, I wouldn't see any potential health risks. However, the small of rats can often be overwhelming. I am currently housing a pair of adults under my desk, and on my desk in my BCI's cage. Now, she's smelling them all the time, and after she started at any movement I decided to move the cage. I think it might also be possible (though unlikely) for a hungry snake constantly smelling rats to eat a cage mate.