Posted: 24/08/2014 at 19:59
Loz..........your Chickens will gradually lay less as they get older. Light levels play a part in how active they are but they should be eating normally whatever time of year.
If one is sickly looking, keep it confined away from the others and seek advice from a Vet...........a good Vet who is experienced with Poultry...not just a vet who deals with domestic pets.
I'm taking it that the poorly Chicken isn't just going into a moult ? If not, I wouldn't waste any time getting her checked out.
Best of luck