It is a thing and it is difficult to find good photos of it because it's not something people want to show off. it used to be more common 15+ years ago but not so much any longer with all the years of improved husbandry advice and knowledge shared about best practices regarding slower growth rate and feeding of boas. It doesn't make the head tiny or anything, it's just smaller in comparison to the body than would be expected, hard to describe, it just looks a little 'off'. They also can grow into it over time from what I've seen.
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