I have a 5" sulcata that I got just a few days ago. I have him in a large plastic container at this time and have filled it half with grass, hoping to provide it grazing substrate. However, it doesn't eat the grass. It will eat some of the leaf lettuce I provide it, so I know it eats. I've read that sulcatas are primarily a grazing tortoise-- do they start eating grass when larger? FWIW, it's St Augustine's grass.