>> I just want to ship my snakes the best way for them to arrive safe.
I don't think there can be any question that Delta DASH is THE best way for them to arrive safe...because it's a legal way to ship the boxes can--and should--be clearly marked with their live contents, so they're handled with more respect. And until they depart and after the arrive they're kept in controlled "animal rooms" at almost all delta offices, whereas the overnight services may have them on trucks for hours--and remember, the driver in almost all instances doesn't know what he's got in the box, what he's handling, because you can't honestly mark the boxes. So no one worries if it's 45 or 100 degrees in the truck, and whether the box is in the truck for two hours or six, just so it gets delivered by the guaranteed time.
The only three downsides of DASH are:
1) you've got to be a known shipper so you have to fill out some paperwork and wait til a delta rep can "inspect" your facility/home/snakeroom whatever. They basically want to see you really are breeding snakes and don't have a weapons cache in your living room, i'm guessing.
2) you have to take the snakes to the airport to ship them. if your primary objective is the snakes' well-being, that's a reasonable tradeoff.
3) with DASH you can only guarantee the shipment to $750 (of course, with the overnight carriers so far, at least, you can't guarantee them at all because you can't honestly state what the package contains). And if there's a direct or non-stop flight to your destination city, you can ship delta priority first instead, and guarantee whatever the real value is, at 50 cents per $100 of value. I figure it's worth $12 to insure a $6,000 shipment.
4) and maybe a 4th downside--DASH costs around $71. Priority first cna be a little less or, ironically, a little more.
the information in the other replies about how to pack is good. I think people tend to overuse hot and cold packs though--unless you've sealed a box with a heat pack inside it and monitored the temp over 12 or 24 hours, with a remote sensor or max-mix thermometer, i think you might be surprised at what goes on in the box compared to shipping without such adjustments. Just my opinion.
peace
terry