I used to work for them and am happy to report that they're still a mighty fine bunch to deal with.
In anticipation of my first batch of mail-oprder chicks I called down to the local office and gave the postmaster my land line and cell numbers. She, in turn, asked if 7 am would be too early to call.
As it happened, I got a call Sunday morning from the regional distribution center to let me know that they were that far if I wanted to come get them. Made many such calls in my own day, and am glad they're still doing it.
I can recall a couple of times over the years when I rolled up the doors on the back of a mail trailer, having cascades of baby chicks come ruching down over the mail bags at me. Usually one of those situations where there was a stack of 500- 600 chicks in one order and something puckered open the corners of the stacked boxes to give them a way out.
Then there were the ducks. We would, on occasion, when there were ducks coming through, open a box and take a few into the break room for duck races on the folding lunch tables. Limit on bets was 50 cents. As you might imagine, the ducks just wandered on the tabletop and the biggest ruckus was the argument over just "whose' duck made it to the other end of the table first. Went on for years until (I suspect) the inspectors caught us through the two-way mirrors. The morning after the last race, a memo appeared on the time clock to let us know there would be no more gambling or molestation (best recollection is that is the word chosen -- we didn't abuse the birds) of livestock on the premises.
So . . . the way things are going there, taking good care of your birds is one of the few old traditions around the Postal Service that you can pretty much find their folks still able to take a universal pride in. Don't hesitate to call 'em up, give 'em your numbers or whatever arrangements, and let them know when they're expected. They'll be happy to help. They've been doing it for a long time.