Don't know what "PBR" is other than an old brand of beer, but Barred Plymouth Rocks???
From a breeder of so-called "heritage" lines, which are incidently, the lines used for exhibition birds. They're simply bred to be much larger than anything you'll get from a hatchery, where the emphasis is on lots of eggs.
If you want birds bred to the breed standard, you must get them from a breeder who keeps the standard as the focus of selective breeding. We can help you out in spring. PM me.