I noticed one of my barred rock hens has a suddenly pale comb. She's not even a year old, and they have all been laying well, considering the cold weather. I separated her from the flock and gave her a good look over. I cannot find anything else wrong with her. She does hang back a bit when they are squabbling over food, but that's really the only symptom I can see. No mites under the wings, feet look good, feathers look good, she is still pretty active. Any idea why she would be looking like this? Do I need to give her any supplements?