I guess a few do seem to have a bit more pale combs than the rest, but I would consider all of them red.
I have felt pelvic bones before, just used the width. Do they really get "flexible" in good layers? I am picturing that when I palpate the pelvic bones, I can feel them stretching a little bit further apart. Is that how it works? I have never noticed that before, maybe I need more practice.
It does take some practice, however, you can download and e-book called "Call of the Hen" which is old but an excellent guide to determining who is laying, who is a good layer and so forth. It can give you some really good information that will help you for as long as you own chickens. BTW it is free.