Different subspecies have different proportions in boa (ssp.). For example a
BCC tends to have a much larger, more angular head than that of
BCI (one of the things I love about the look of
BCC 
). There is also the possiblility that the faster grown boas can have smaller heads in proportion to their bodies than that of the slower grown boas. Power fed boas can appear to be "pin headed" as the body grows much faster than the bones of the skull. There is generally not a problem health wise for differnt head sizes when compared to the body size except for in extreme cases.
