Every breeder is different but many will not ship below 30/40 degrees. If they do, the box and materials must be extra perfect in every way. Especially the heat packs. I personally would never ship below 35/40 degrees.
As for the OP and this last post before me saying they warmed up the snakes as fast as possible, this is not always the right thing to do with reptiles. Read this report by Dave Barker of VPI.. If the link doesn't work here is a quote from the report. A snake showing signs of IBD after fast warming up would be a normal reaction. They do not always come back from this but if this is what is wrong, it was preventable..
"As temperatures drop, snakes become less active. At temperatures
of 13EC (55EF), most snakes move about slowly, flick
their tongues out in slow motion, and will drink water. As
temperatures drop further, most snakes become torpid and are
unable to move or to react to stimuli.
As temperatures decrease below the point of torpor, there is
an increasing chance that when warmed up the snake will suffer
cold shock syndrome [CSS]. However, rarely are snakes killed
outright when chilled to core-body temperatures of 4–7EC
(40–45EF) for only a few hours; if the duration has been short,
most will warm up with few, if any ill effects; however, after
even a quick chill, some snakes may suffer CSS or other problems
upon warming up. At temperatures below 10EC (50EF),
pythons suffer an increasing chance of dying as the duration of
exposure to cold temperature increases.
When warmed to temperatures where activity is possible,
snakes suffering CSS will not be able to move in a coordinated
manner. They may exhibit what appear to be violent seizures if
disturbed or handled. Snakes with this condition may die within
48 hours of being warmed; if they survive past that period of
time, they likely will recover, but full recovery to normal coordinated
movement can take more than a year."
http://www.vpi.com/sites/vpi.com/fil...fCold_BCHS.pdf