It is okay to use in addition to the rat block as a treat. Be sure they always have fresh, clean water to drink in a demand-type water bottle, not a bowl that can be tipped over. You can add healthy table treats my rats think green peas, corn on the cob, romaine lettuce, dry pasta twirls, bananas, cooked oatmeal, avocado, and chicken bones are the best treats. As far as sweet treats go, my boys will move mountains for Vitakraft s yogurt drops for hamsters. Of course, they really love chocolate, but like me, they need very little.
Some people use cereal as treats just the individual pieces.
A few sunflower seeds or nuts are usually adored.