I've purchased 4 adult and 6 juvenile ball pythons. Haven't had any problem with the adults, either behavior, temperament, or health. Haven't had health problems with the juveniles, but a couple have been kind of nippy. Asi understand this is fairly normal for the small ones, but 2 have retained this behavior (haven't weighed recently, but they are over a year old now), so I'm having to give them extra attention and handling to try to calm them down.