i would let them know a few days before you expect them to arrive at your post office . i ordered some last week from meyer in ohio. they are being shipped next week to my post office. i should get them on the 10th which is next thursday. i will remind them on tuesday i have a order of chicks coming in. 2 years ago i ordered chicks and i waited for the post office to call they told me they open at 430am so i was up waiting for the call and 7am came and no call. so i called them and they were there outback with someone elses order the po clerk thought they were all one order i rushed right down to get them and they were all fine and dandy. this year i think i will be waiting at the post office backdoor when they open at 430 am thats when the truck shows up.
You should always tell the PO the days before a expected order of chicks. For one, they may need your number... for two, it gives them the heads up and let's them know that you are eagerly waiting for their call.
I even go so far as to call the PO again the Wed and Thurs that the chicks should arrive. If they don't call me by 8am... I start to bug them!!!