Please Help - What could be wrong with my Pullet

[silky098]

I am really concerned about my copper black marran who is about 19 weeks old. She doesn't lay and looks a bit young to still. She is not eating too well, she is bottom of pecking order, she seems a bit withdrawn and slightly droopy comb. She also seems tired and sleepy. I have only been keeping chickens for a months so I don't have much experience. I feed her a layers mash and water with ACV. Also corn late in the afternoon. I would appreciate any help/advice. Thanks.
Silky

 

[redhen]

Can you try to isolate her in a seperate cage...just so you can see exactly what and how much she is eating? Have they been de-wormed? Do you see any teeny tiny bugs on her? (lice or mites will make them weak if they have them bad enough..) look for small whitish egg clusters at the base of the feathers..close to the skin. Check the vent area...and under the wings..