Hi, I just started my medium/young rats on a new diet; they're eating the little vita blocks that are recommended by the petstore and this website. I follow the directions on the bag and give them 3 blocks each per day. I give them their food in the evening and in a couple hours, they're gone. So, am I right that they don't need any food until the following night? Aside from a few treats of course. They always seem so hungry!