I have a new mixed flock of 20 week old pullets, but I am concerned my Black Australorp may be a roo. “She” may be laying though because I think she is the only one that will lay dark brown eggs out of my pearl star leghorns, amber links, barred rock, silver laced Wyandotte and Easter egger. There has been no crowing and she doesn’t show any other rooster signs in fact she’s very shy. What do y’all think?