Molt is in a sequence and starts at the head and neck, down the back, across the breast and thighs, then tail.I still find it a little worrying that she would only be molting around her neck, which could her more likely to get an injury or death because it's not well protected. Also my chickens tend to molt in the fall so that's another reason I don't think that's it. And in response to the question there are feathers coming in on one but the other two haven't started growing their feathers back even though they've been featherless for a month or two.
Not sure why molting would cause injury or death than any other time?
The featherless back is either from roost, picking or a combination.
It's not uncommon for hens to molt late in the year.