I know the photo quality is poor but my FIL bought these as Jersey Giant pullets that hatched in Nov. which would put them at about 6 months old? They're tail feather area is super ratty and torn up and to me ( I have zero experience with the breed) they look like younger roos. He says the lady he bought them from say they take a really long time to mature but I'm starting to doubt this. I only see the birds about once a week.
Here they are when he got them
Here is the bigger one now. It's shoulder feathers are lovely with a nice green sheen, but its back, neck and tail feather still look pretty shredded.
For what ever it's worth, my JG typically has a ratty tail too. I think it's because she's SOOOO BIG, that it gets messed up when she jams herself in the 12" by 12" nest box to lay her egg. She usually preens it back into place later in the day.
Your girls are not that big yet. But I wonder if they are rubbing their tails up against a wood wall at night on the roost or something like that?