You can't go by the tracking number, unfortunately, and that's out of MPC's control. The first year I ordered chicks I followed the tracking closely. They were shipped on Monday, and the Post Office tracking said they were DELIVERED on Wednesday. But they weren't. In fact, when I went to our local post office our postmistress, Jan, who knew for days that I would be expecting them, called the main sorting office in Casper. Yep, there they were, still sitting in the loading facility in Casper, Wyoming, and the temperature was 17 BELOW zero!!! Jan left orders with Casper that when those chicks were going to be loaded for transport to here (a 6 hour drive, mind you) they were to be placed in the cab with the truck driver.
Those chicks arrived on Thursday, one full day after the US Postal Service said they had already been delivered!! How can that happen? Well, as our postmistress investigated and told me, they (PO) can sometimes consider the final "sorting facility" as the "destination" because after that it's a matter of narrowing down from there. Yeah. Stinks, especially after we are told we have no choice when ordering chicks but to order "express shipping" because they are live animals. MPC has a disclaimer on their site that explains that the usual express shipping "guarantees" don't apply, and again, that's the PO's call, not MPC.
The next year when I ordered chicks from MPC, I was prepared for this. Sure enough, shipped on Monday, delivered (on paper) on Wednesday, actually received at our local post office on Thursday.
And by the way, chicks received from Meyer have nothing to do with My Pet Chicken chicks. Alex (@MyPetChickens on this site) has explained the misunderstood "middleman" theory. It is explained on this page of this thread.
I hope this information eases your mind a little bit, although I know that until you open that box you are going to be on pins and needles. While I did lose a couple of chicks in that first shipment which was stuck in Casper in subzero weather, I didn't lose single one out of the shipment the following year - with the shipment date requested for later in the season. I think the difference is curbing our enthusiasm and ordering for delivery at a more sensible time of year than I did the first time! No more February chicks for me!!!