I read on here about this couple had heard from an old timer ...you the chicks up by scruff, like a mother cat does with a kitten and the females will let their legs hang and the males tuck their legs up. The couple Tested this theory on a group of chicks already sexed at the feed store and sure enough it worked, so I tried it on my 3 day old chicks and 3 let their legs hang and 1 tucked up...try it! Let me know if it works for ya!