What a good looking hen, I have 2 like her except my rooster has torn many of the feathers off the back and sholders of one, looks like she was scalped by a lawn mower. I hope her feathers will grow back when she molts this fall. My Plymouth Rocks give light colored shells and one produces shells that are almost like porcelain. My Golden Comets give a nice brown shell. I would be curious to know what color the shells are that your Plymouth Rock hen lays. Also, my Plymout Rocks are very vocal, not loud just always talking up a storm, I believe they are happy hens.
I read a story once about a couple of boys who were given some chicks and they raised them and became interested in chickens so they went to the state fair and saw many other chickens for the first time, they came home and compared their chickens to what they saw at the fair and decided their chickens could take first prize at the fair next year because they were so myuch bigger. They entered the chickens and were dissapointed not to take a single prize. The judge explained to them that even though they were big, healthy and overall good looking they didn't conform to the standards of judging. I am not saying that is the case with your hen because I don't know what the official standards are either. Here's what matters, fat or skinny, pretty or ugly if you love them that's all that matters.