I picked up my two RIR hens at the same time and I was told they are over 20 weeks. I've only had one of them laying so far. So as I am learning more from this site, I am starting to notice things different about them. The laying hen is a little bigger, stands with her tail up all the time (the other does not) and her comb is bigger. She just seems like an older chicken. She was also the lead bird when I let them out for the first time yesterday. Does it seem like they may be a few weeks apart in age? My profile picture is of the two hens from yesterday. Not sure if you can get a clear view of the combs or not though.