I hauled livestock for a year back in the early 70's. Mostly Hogs, from points south and west to philly. Not to justify anybodies driving habits, but the reasoning behind moving along after you're loaded is that the buyers pay on the weight they receive at the slaughter houses, not the weight they were bought at. So, any peein or poopin that is done enroute, is at the haulers expense. I know, strange logic, but that was why I was told to hurry to Iowa, and when I left there loaded, don't stop for anything but fuel and coffee till ya get to Philly.
One good aspect is , ya can clear out the counter at the truckstop cafe real quick.