She's crested so may be suffering from some brain trauma as well.
I would add 400 IU Vitamin E and 1/4 tablet B-Complex to daily routine for a week.
If I give vitamins and a bird is not eating/drinking well, then I dissolve the vitamins in a very small amount of water and syringe it into the bird. That way I know they get them and don't rely on them eating.
Looking back at your first post - you have 5 five week old in a 36sq ft space that includes 2 roosts and swing. I assume water/feed also are housed in this space as well.
Giving them more room may solve your picking/aggression problem. I know there's a "4sqft Rule" but that really is a suggestion. More is better. I'm sure you know this with your having adults - they can get cranky and on each other's nerves - 5 week olds, get on each other's nerves too. I've never found separation to settle a bully as a solution unless it's permanent separation. A top bird/confident/strong bird is always going to be top regardless of how long they are separated. At least that's my experience and I have tried it more than once. Space has been a solution for me - that or culling. Sometimes having birds that are not compatible personality wise can also be an issue. I like having a mixed flock like everyone else, but usually don't put mild mannered breeds with stronger willed breeds (in confinement) - it can create a lot of drama.
Photos of how they are housed and the set-up may be helpful.
Pullets can be as aggressive as cockerels at that age - aggression doesn't always mean it's a male.
