Mali uromastyx wont eat!?

I got my mali a week ago today and hes hardly touched his food..his tank set up should be good..its 72-80 at night with an under the tank heater and 85-90 during the day on the COOL side, the cool side also has a UVA/UVB light. The basking side ranges from 118-128 F. Hes only about 6 months old, he may even be a little younger. His substrate is small bird seed and hes in a 30 gal aquarium for now..Once he's settled in ill move him to a bigger tank. I've only noticed his food 'messed' up twice..but he has bowel movements every day. Im feeding a spring mix with bok choy, collard greens, seasame seed, ernut squash, and shredded carrots. I've also tried peas and red, yellow and green peppers and I dust some calcium on top. Should I be concerned???