I am not really very worried that they are not laying, our oldest girls are only 18 weeks old, but I am curious. The three oldest are a RIR and 2 RSL's. I also have three barred rocks and all of them have bright red combs and are pretty big. Is it possible that they are ready to lay, but aren't laying yet due to the heat? It's been up around 100 degrees for several weeks now. I know they are young, but their combs turned super red a few weeks ago.