Hens protecting chicks will puff out all their feathers to make themselves look bigger.The women i got them from and + i looked up the fanning of the tails. if you hold the chicken head away from you/tail feathers towards you and lean the chicken foward/down the tail feathers will(if this is true) Fan out if they are a hen or stay together if they are a roo. The reason they are said to do this is when a hen is protecting her chicks her tan will fan out to i guess make her look larger? I am not sure i dont remember how it was explained. But if this is a way to tell then she is a hen. If not then i guess its a wait and see. I will take some pics to post tomorrow of the side. Its late and i just got home from work. I really hope she is a hen. I just found out my other chicken which is a Amber star is more likely to be a roo. Gah i have no luck.
This has nothing to do with determining gender. One of those other wives tales.