Does a rooster know when a hen is ready to breed?

[oldhenlikesdogs]

Combs enlarge and get more red when birds are fertile in both sexes. The comb is a visual sign to everyone, including roosters who is fertile and who is not. When hens go out of production the combs will shrink and lose coloring signifying they are no longer fertile. Roosters shouldn't waste energy breeding hens that aren't currently fertile and will focus on those that are.

 

[chickengeorgeto]

In my opinion the hen knows with more certainty when she is ready to mate than the rooster does. When the hen is rooster ready it will be difficult to keep the two of them apart.