I'm sorry....they are Barred Rocks. I'm an old guy and I grew up knowing them as Plymouth Rocks. It wasn't until about 10 years ago I first heard them referred to as barred. I haven't seen any differences in them other than a few hens have more white on some wing feather tips. They all have "normal" combs and leg coloring and everything else. No white lobes.
As a kid my parents had an egg & meat business and we had a couple hundred Rhode Island Reds we used for the egg and meat business. Once Pop took me with him to pick up the chicks and I saw the Plymouths for the first time. I was enamored with their looks. I asked him why we didn't get them instead and he said because we use RIR's......end of story. I swore when I got old enough I'd have a pasture full of them. For many, many years I couldn't have chickens in Scum City (Houston, TX). Until July I had to settle for what I could find around here. With the new coop and no chickens I got my wish for a 100% PR flock. I hate the idea there may be a lurker from some other breed in there! LOL
My wife loved our old flocks with all the colored birds. As much as I hate to admit it I did too! So as these die off I'll be adding Buff Orpingtons, Black Australorps, White Rocks and more Welsumers and Easter Eggers. The colored eggs were a favorite with friends I shared them with.