The receiver should check the temps when you arrive and count the product. If those are in order, you have done your job.
If there is a problem with the size of the chicken or the way it was processed, that's between the shipper and receiver. You have no control over that.
That simply means that they did not do a full inspection of every case. It is possible they might try to be skeevy and come back at you later with a claim, but at the same time, they need to protect themselves from the shipper selling product that was allowed to go bad before being shipped.
From our point of view it's bothersome, even worrisome, but from their point of view it's risk management.