Oh, that sucks. That has happened to me a few times. January thaw sends the birds into a molt, then it freezes back up again. It's often the hens who miss their Fall molt. Never a fun thing to deal with...
Poor bird. It might be helpful if while she molts if she's separated to a quiet place with smooth walls. During molts, the new pin feathers can be extremely painful, so any touch can be terrible. You're saying she's 6 yr. old and you don't see any actual bold spots; she might be dealing with...
Ok, I looked up both to compare... The Niederrheiner's tail is a darker gray. Of the Lemon Cuckoo Orpingtons that I've seen with grey in the tail, the gray is lighter (if it's even in the tail). So I say your rooster is a Niederrheiner. :thumbsup
Reminds me of this Dude Perfect Overtime episode on YouTube. They do this thing called Wheel Unfortunate and one of the guys who got picked to spin the wheel had to get his eyebrows shaved off. :lol: