it is my belief that chams cannot convert beta carotine into pre formed vitamin a. it has been found that chams deprived of preformed vit a in their diets develope eye problems & problems shedding among other things. Some may disagree but you will find that they, more than likely, use a huge variety of feeders. it is not proven which feeders can make the conversion. i dont think that crickets can. if you are feeding mostly crickets, i would use a multivitamin like reptivite, which contains preformed a. I also wouldnt use a product containing performed a if it doesnt contain d3. With more research on the subject you will find that ones who dont use a multivitamin with preformed a offer d3 only once or twice a month. i use reptivite with d3, 3 times a week, with the belief that the d3 & pre a balance eachother out. No ill effects to date. YOur best bet is to go over what you feed & gutload & figure out whats best for your situation.