It's hard to say. They all have their own preferences. It could just be habit based on what has been available to him. If you want to switch you could try just offering one or two fresh/live items for a while to get him used to it.
Follow up question: she seems to have stopped eating. It has only been a day though. Yesterday she didn't eat and i changed her tray two times just in case but no dice. And today i noticed that her "beard" is sort of saggy. It looks like more noticable than usual. Anything I should worry about?
One last question: she ate a little bit yesterday so im not worried but she is spending a lot of time in her hiding spot. And she hasnt pooped in a few days. I saw her trying to poop this morning but all she managed was a tiny little ball. Nowhere near normal. Should I get her checked out?