You'll see saddle and hackles after the chicks finish up all of their juvenile moults. I think that's somewhere around 3-4 months old? Usually my little roosters have combs and are crowing before their feathers give them away
The rooster mature much faster than pullets. If you have a roo and it has not crowed watch the comb and waddles. Very early before they crow and show the saddle feathers and the curly tail that comb will go bright red long before your pullets turn red.