How do they know?

[bigredfeather]

Last night I noticed one of my roos trying to mate with a smaller rooster in the same pen. It got me to thinking about how do chickens know what sex other chickens are.

Anyone have any insight on this?

 

[Andi]

I would guess its no different then how we humans tell the difference. Maybe your roo was just a bit confused.

 

[bigredfeather]

So you think it is based on visual factors?