Here's another link for those that like reading studies:
http://journal.frontiersin.org/article/10.3389/fevo.2016.00094/full
I originally posted the first because someone said they weren't sure if chickens could smell. There is an avian pathologist I know that studies the ears, eyes, nares of...
I thought I was, lol. I mean no disrespect to any BYC members, and I understand why people don't believe the offspring thing because I've had siblings mate, father/daughters, mothers/sons, etc, though this has been mostly with birds caged together. Personally, I think it's an interesting subject...
I guess I read things a little differently... That one doesn't make sense to me, so I'd have to read more about it, but much of the other stuff I have read before, so I think the majority could be true. Have you read Gail Damerow's books, or the chicken chicks website? Plenty of misinformation...