I do use Listerine regularly in the bath water but I agree that it is probably most useful for discouraging mites and helping with bumblefoot issues.
Debbie, my hen is the same -- she scrambles up the bars of the cage like a monkey and flies only very short distances because of her feathers.
Monique, I think what happened is that I had my Forbes hen in with some of my other hens during their resting period and the other hens (particularly my Stars which are uncharacteristically quite big and tall) prevented my timid little Forbes from eating much of the time -- I noticed that my Stars like to tower over the smaller birds and peck them and pull at their feathers. Naughty birds.

Does the ACV go in her drinking water or her bath only?
Anyway, they all molted properly except my Forbes so I have since corrected this issue -- the Forbes and the Stars will not be together again but I am trying to get my little hen back into condition so she can molt and breed.
Sally and Gary, Thank you -- I will add additional feather supplements as well -- she is getting fortified eggfood every day but maybe it is not enough.
I was wondering if a bit of Epsom salts or Boric acid might help in the bath water, too?