i have 4 adults and i usually give them mealworms that are an inch, maybe a little bigger, just well gut loaded, those are their favorite by far, but i have seen them go for small worms and the occassional waxworm. the crix probably won't work out i very rarely offer them and they take quite a while to get eaten. mine also like the beetles mealworms turn into. if none of that works a slow moving, non climbing roach species may be a good option. i see mine digging for food all the time and know they are eating well, so i just throw the food in there, but you may want to consider on of those worm dishes with the little rim to keep the worms from getting out. i have also heard of people offering some vegetation or even baby food, but mine have never parteaken so i do not recommend this....does he/she have a good soak dish, that may stimulate appetite