Well... kinda, sorta, maybe, with about 50:50 success. Read this:
SEX IDENTIFICATION IN PUREBREDS BARRED PLYMOUTH ROCKS
It had long been recognized that the size of the light colored head spots and the leg color in Barred Plymouth Rocks varies in the two sexes. The males tend to have larger head spots and the females to have darker colored legs. However, this method has not been accurate enough to be of much commercial value.
Quinn and Knox (1939) attempted to separate the sexes of Barred Plymouth Rocks by means of the intensity of the black pigment in the down and legs. In different lots of chicks they report 83.5, 86.1 and 91.8 percent accuracy.
Jerome (1939) describes a method of sex identification in Barred Plymouth Rocks based upon the regularity of the outline of the head spot rather than the size of the spot. Those chicks having head spots irregular in outline and scattered in appearance are males while the females tend to have head spots with more regular outlines. The author claimed an accuracy of 90 percent or better when considering only the head spot and 95 percent if the color of the legs was included in the consideration.
The Canadian Department of Agriculture (Anonymous 1941)issues an excellently illustrated bulletin describing the method. It is stated in the bulletin that the method is widely practiced in Barred Rock chicks by commercial chick sexers.
Sex identification is based upon outline of head spot, color of legs and shade of down color. There are several types of male and female head spots
The three traits, head spot, leg color and down color, when taken together results in about a 90% accuracy sexing the Barred Rock chicks from hatcheries, these days. The darker down color, much darker leg fronts, and more regular, smaller heads pots are usually, but not always, the pullets. There are individual variations among chicks that will often lead you to the wrong conclusion or have you sitting on the fence till that great big red comb pops up and he crows. And I've had them lay from 19-24 weeks, just depends, but most lay by about 23 weeks old.
Maybe you can sort it all out.