It's really hard to say David. If they were perfectly fine when they left your place, then the logical thing would be to think that this happened during shipping. Even then, there could be so many factors caused during shipping such as drastic and quick changes in temperature, pressurization and depressurization of the plane, even being put next to possibly toxic cargo, not necessarily toxic to humans but perhaps to reptiles, cannot be ruled out.
As far as "head spinning" or "loss of balance" goes, I'm sure you know as well as the rest of us that there have been reports of things like star-gazing, spinning or even back crawling from some hogs, some attributed to genetic traits sometimes found in Pink Pastels. Of course I've heard of other non-PPA related instances and even myself acquired such a specimen that came as part of a large shipment of hogs. Oddly enough, the seller either didn't notice the severe head wobbling or it happened during shipping as well. However, I received 12 snakes in that shipment and only that one exhibited head wobbling, so I think the odds would rule out transit issues. Other than his head wobbling, he's an awesome snake, very active and aggressively hungry.
I also hatched out a small group of female Anacondas that have a tendency to lay and/or crawl on their sides and even on one rare occasion I saw one curled up and laying on it's back which caused me to freak out a little because I thought it had died until it woke up, looked at me, flipped over and has never been witnessed doing it again. It's only these 3 females from this one clutch that has several other siblings that don't exhibit these behaviors, just these 3 particular girls and it's not even something so severe that it's shocking, just minor and odd enough to be noticed if you are paying attention. So who knows?
If I were you, I'd ask the guy to try and take video of those snakes if possible and email it to you, that way you can understand exactly what he is talking about.
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Troy Rexroth
Rextiles
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