If he's not aware of the temps in your area - first shame on him for not checking and second DO NOT LET HIM SHIP. That is way too cold. Even with a heat pack or two - anything below 40* is pushing it - although plenty of people will ship down to 35* but 20* is definately a no-no.
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Tosha 
"Nihil facimus sed id bene facimus"

11.42.0 Ball Python (Harry and Fluffy and gang)
1.0.0 Angolan Python (Anakin Skywalker)
0.0.1 Green Tree Python (Verdi - yeah I know but my kids love the book)
0.1.0 Bredls Python (Smurfette)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Desert Tortoise (Pope John Paul aka JP )
2.2.1 Fish (1,2,3,4)
0.0.0 frogs rescued from pool skimmer