Jerky, wobbly head movements, sleepy, not eating 2 month old ????

[sarahlouise]

Hi, ive also got a chicken with the same problem. I got 4 chickens when they were about 16 weeks at the end of July. Yesterday she wouldnt come out of the coop, she was falling over with a wobbly head and very sleepy, her head was jerking almost like she had a knock to the head. I seperated her from the rest she just stood there all day and wouldnt eat or drink. In the afternoon she started to peck about but not eat anything. Then sort of started to perk up walking around making a noise and laid an egg. This morning she just stood on her purch didnt move and now im giving her water and she sleeps all the time. While she sleeps her head seems nod up and down as she takes breath. Shes hasnt eaten anything all day, and has not moved. Its almost like she can not see or hear. This has happened all of a sudden. All the other chickens seem to be ok . Ive looked around on the net and im unable to find anything that matches her condition.
I dont know what to do for the best any ideas? Many thanks Sarah