Good luck and keep us informed, there has been a lot of good advice given by members here. his is such a good group! Your best bet is to deal direct with your Post Master.
I am fortunate, my delivery guy (Rubin) has ducks and is quite good about package deliveries. I have to go to Montpelier for live birds but they are very nice for a busy city PO. Not all Postal workers are bad.
I remember when I made my first chick order (spring 2001) the PO had special delivery people who hauled stacks of those LOUD CHEEPING boxes of new chicks to people on Sundays. They don't do that anymore, I sure miss it!
The PO can be a pain too, they moved a very good employee from the PO nearby my job because she complained about abuse from a coworker. This was a person who went out of her way to get to know each and every customer by name and at a very busy PO too. She was the first person to reach out to me when I moved to Vermont in May of 2006. Her bosses knew she didn't drive so they transfered her to a very far off PO just to inconvenience her even more. That's just cruel all the way around.
People in the town put signs on the road and took ads out in the newspaper in dismay of her being transfered and the PO ignored them. Town just isn't the same....