A great thing to let your rats chew on is rawhide. My rats just love rawhide, I just went out the other day and bought a new kind by Fortum, but they also enjoy Petcetera's rawhide chips.

Here's a list of food you shouldn't feed them. There is alot, so be careful. An informative forum to go to is www.petratscanada.com/forum but everyone there is really touchy and pretty arrogant so don't p*ss them off..They get mean..