In answer to your question i have a buff chantecler who sings the egg song and sits in the nest. just because one is in the nest doesn't mean it is a hen. once i let my buff chantecler roo, 2 buckeye hens, and 2 andalusian hens outside to run around. none of them had laid yet that day. i was walking by and twice i saw one of the hens standing next to my roo and squawking, after they did that the roo would get down in a likely nesting place and sit for a while, later I would find an egg there from the hen. I think that the hens asked the roo to go and check out the place they wanted to lay to make sure it was safe for them. Roos will usually sit in the nest to make sure it is safe for the hens, so if one is in the nest it doesn't necesarilly mean they are the hen.