diet

I wanted to vary my dbt diet, but they seem to be picky eaters. Right now they eat calcium pellets, brine shrimp, regular shrimp and silversides. I have tried beef hearts, grammarulous pellets(not sure on the spelling of that one) and blood worms and they dont seem to like any of them. Does anyone have any other suggestions? Also, I was wondering if these turtles could be returned to the wild? I have had them since they hatched and they are ten months old now. I believe I have two girls and one boy, I was told that after a certain point they should not be returned to the wild. Thanx