I am not sure what to think about the mvb's. I have bred and raised chuckwallas successfuly to the 3rd generation using only halogen floods, cool white flourescents and oral supplementation. However this wa not the case with petrosaurus and crotaphytus. Only after a few months of the chuckwalla protocol I noticed trembling and retarded behavior in those two insectivorous lizards. It got so bad with the petros that I lost a couple-they went into convulsions and died. I was desperate so I went out and purchased a bunch f the zoo-med mvb's. The difference in their behavior was immediate. Within a few days the trembing stopped and they started acting like normal lizards again. Maybe I just could not get enough oral sups into the lizards by just dusting their food. Anyway I went to mvb's on all my animals after that.