how long does it take a french blue marans start laying eggs?

[swamperkk]

no sure about this does it take a chicken to start laying eggs at 6 months or is it longer? I have some french blue marans they are about 3 months old,hard to tell which is the rooster from a hen,i seen two roosters trying to crow but they all look alike,i know i have 3 hens because they have a tiny comb