I have one hen from the second arriving group who was lowest of the pecking order in her group, then of the whole, and since the more recent arrivals, she's stayed lowest of the entire flock. She is just naturally a low status hen and she had started to get blood drops showing on her bald bum so I started letting her out of the pen all day (the rest come out at lunchtime til dusk) and feeding her separately so she is getting enough and has space to roam on her own most of the daylight. She goes back in with the rest when they go in with their corn and roost and there is already signs of feather regrowth tho they still pick on her.
I've a second one (a Black Rock) showing signs of being next lowest now

who was lowest of the first group til the second and third lots arrived - I started letting her out too but she then picked on the first lowest while they were sheltering from sleet in the same place, so I sometimes let herout all day too but not at the same time as the first so they both get feed. I spend so much time managing hen politics

Guessing your lowly hen is like mine, just low no matter in what size of company.. Mine is way too nervous to let me pick her up and spray her but she's got adept at getting to the gate to be let out and is accepting the odd raisin treat closer than before so I'm biding my time til I get my hands on her without stress. She was a commercial free range and bald with a deformed neck and damaged wing when she arrived 15 months ago, so she's already better off than she was then or would have been if she'd not come here.