Blackshoulder chicks aren't too hard to sex after you have watched them for awhile.We have Opals,India Blue,Purples,Silver and Midnights in black shoulder. One dead give away is for males the feathers will get more and more black lacing until the entire,or most of the feather is black.Hens primary flight feathers seems to also give them away sooner turning rusty brown gives them away.Males will have the lacing on top of their backs,right behind their necks on these feathers where hens does not.