I don't know for a fact how the machine does it based on feather shading, but I do know for a fact that there is a thing about chickens: sex linking in hybrids.

I don't know for a fact how the machine does it based on feather shading, but I do know for a fact that there is a thing about chickens: sex linking in hybrids. When you hybridize certain pairs of breeds (e.g. reds and barred rocks) the hybrid chicks show different feather coloring at the time they hatch. Hybridization can also produce offspring which are for instance more productive egg layers. Being hybrids, they don't breed true. Not all hybrids have the same consistent sex-linked characteristics.