She's about 3.5 months and has HT 2018 pellets.
She also has access to a mix containing: kale, spinach, white mushrooms, carrots, apple, persimmon, parsley, basil, cilantro, strawberry, bell pepper, banana, ginger root, fennel seeds, chia seeds, and some Oxbow Regal Rat pellets. There may be more in there, but I'm at work and can't remember it all off the top of my head.
It could be, shes a bit young to rust. I'd try giving her a couple meals of liver a week for the next week or two and see if she improves with her next moult. You may be watering down the nutrients in the blocks to much by feeding all the veg depending on how much you feed.
Just cut like half a chicken liver and give it to them. From what I read it doesn't seem to be dangerous and is even better nutritionally raw. Of course if anyone has better in feel free to correct me. And at that age I don't think a half piece of liver a week will overdo it even if it is a molt.
Not to step on anyone's toes, and I know rat owners have done it without problem ......
I know people are saying that raw is fine, but these factory farmed organs have bacteria that is dangerous and resistant to antibiotics.... Rats and other animals have been known to get bacterial infections from these raw meats. The bacterial and toxins are not like they would find in the wild, even while scavenging.