Post office tracking is NOT like UPS where you see every stop along the way in a timely fashion. The PO usually isn't updated until late evening, and even tho then order may sit somewhere for quite awahile before it moves on. I always have stuff before the tracking number catches up.
With basic ground service (I am getting supplies) on UPS, my delivery date is Monday. My packages have been sitting in Chicago since Fridaynight. Since regular ups doesn't deliver on weekends, it sits there in Chicago till Monday. They they will have a flurry of activity and it will go Bedford park and say something like "4:30 am out for delivery." Of course delivery could be in the evening but at least it's coming.
IF UPS did accept chicken/eggs - you would know where you package is - of course the UPS men seem to throw things as often as USPS. Most boxes I receive are caved in somewhere- the trick is to solidly fill a box - with insulation, , peanuts, newspaper etc. so it holds it's shape firmly - of course then shipping weight is higher - oh well.