We have 1 dark Cornish pullet and the 2nd one looks like her, in my opinion. Ours was sold to us as a pullet, so I assume that's what she is until she proves otherwise.
The feathering on the first one reminds me of my favorite EE (see my avatar), but it doesn't have muffs so that's probably not what it is. I wouldn't say either of them have large enough combs yet to say for sure that they are roos.
I do know that neither is a barred rock. That's for certain!
I think they are both partridge rocks. I breed giant partridge cochins and the colors are definately the same. Some will get alot of black on the breast for awhile.