hehe, how big is your post office?
I'm in Ohio too! Go Buckeyes!
GO to the Post Office several days at least before they're expected, tell them you are expecting live day old chicks. Let them know the scheduled date, and give them your phone number, and an alternate number too, just in case!
Sometimes they'll call you WAY early, as soon as the truck arrives before the office even opens... they might tell you to come to the back loading dock door, sometimes they'll wait till the PO actually opens.
When you get there, open the box in front of a clerk so you can see if any died in transit... most hatcheries require that so it's clear that they died in transit, not a day or two after you got them home.