Our roo has sired a number of chicks, while most were killed on mass by a viscous cat, the all appeared to be developing into roo's. Since then more have hatched, 3 out of four were boys and the "hen" is developing a worrisome tail. I know is possible for a human man to only make XX children. Is it possible for a roo to sire only male offspring? He is a dominique/java mating with mostly malay/java hens.