i think you were asking me about degus, not too sure though as what you mentioned sounded like chinchillas too,

degus cannot eat too many other foods, then the pellets they are fed, they can get diabetes very easy if you give them the wrong foods,
when i had mine, they only were fed pellets, and hay,
once a week i would take two walnuts(cause i had 3 of them) and slightly crack them a bit, and put them in the cage, the degus would chew away at the nut, (helps their teeth) to get to the treat inside, but this was the only foods they would get,
i have read on some sites, that they can have many different things, but with the risk of diabetes, they are healthier and can live longer, if they have a restricted diet,

most(not all) degus can be handled a lot, as they are affectionate and very social, i was told they will not jump if they dont think they can land safely, which i noticed if you hold them up they dont try to jump away, but still be careful when handling
i had 3 females, as they do like to live in colonies, but males will fight,
and with the dust bath, only leave the jar(i used a fish bowl) in the cage with them for about 15 minutes, then take it out, they love the dust bath, and it is so cute watching them take a dust bath, i personally like the finer dust more than the sand, as it seems softer to me, and does a better job of cleaning the degu, and chinchilla fur
there were a few occasions, where one of my degus used to escape their cage, i would use the dust bath to entice them and catch them again, it worked everytime
i gave my degus to a friend and she made a beautiful cage for them much nicer than the cage, and then aquarium i had for them
she bought a big square cage, and set it up with some branches that criss cross through the whole cage, and put shavings(only pine)on the bottom, with a few of those little log houses in there, they love it, and use up their energy bouncing around on the branches