We have six chickens (three australorps and three leghorns) which all were doing well until about a month ago. Then one of the australorps started to act different and her comb started to decrease in size and became dull. Also her pupils look dilated and dull. She is not laying and acts timid at times. Now another of the australorps is starting to develop the same symptoms. The leghorns are all fine. I am new to raising chickens and need any helpful advice or suggestions. Thanks.