I have six sex link chicks 3 red and three black. They are approximately 4 1/2 months old. Within the past week one of the hen has started showing signs of being a rooster. She is crowing and aggressive towards the other chickens and definitely the most dominate of the six. How do you tell if you have a rooster or just a hen taking on the roll of a rooster in the absence of a rooster in sex links?