My girls are 20 weeks old. One is laying, rather irregularly for about a week, and another is starting to be led to the nest by Cogburn, our rooster. This afternoon, one girl was in the dust bowl, and her comb was so pale, almost white. When I spoke to her, she got up and it turned bright red. When she walked away from me, it turned pale again. What's up? Is that a mating call or something?