Okay I know you are going to laugh at me and I don't care. I'm a fan of using the ring on a string trick to see if they are male or female. once the egg is progressed far enough along to definitely be one or the other. I've seen it so many times and be right I don't care if anybody believes me . I'm a Believer.
I watched my daughter in law do it once over her hand with her gold wedding ring on a string. Kelsey's having twins, a boy and a girl. that ring went around in a circle once and then back and forth once. then round in a circle once and then back and forth once. it was just amazing to see. I have also seen at old-time farmer do it with chicks correctly.
I am not laughing at you, I am angry you didn't say it earlier, lol. my broody has just hatched 11 chicks.