Can I help a sick chicken?

[Fields Flock]

One of my 7 month old Plymouth Rock hens has suddenly started to roost on the floor of the coop and the other chickens are aggresive towards her. The feathers on the back of her neck are not fluffed up like usual, and I can see her skin. Her comb also seems to be shrinking and is not bright red anymore. Can anyone offer advice on how I can help her?

 

[delisha]

Give her a seperate area away from the other birds. Offer her some ACV in her drinking water.
Do an exam on her
Is she lighter than you remember?
Weigh more?
Does her belly feel hard?
Does she smell different on her mouth or her vent?
How do her eyes look?
Take several pictures of her and post them
If you have some old pictures from a few months ago, post them too