We have 8 chicks, one set of four (2 BO and 2 Ameracaunas) is 4 weeks old and the other set of four just under 3 weeks old (2 RIR and the Barred Rock and a Golden Wyandotte). Everyone was getting along great until a day or so ago when the RIR from the younger group began to peck and pull feathers out of the Barred Rock, also part of the 3 week group. "She" doesn't pick on any of the others...just goes right for the Barred Rock. We've separated her temporarily...could this 3 week RIR be a rooster??? Anyone have any suggestions as to how to settle this issue? I'd love your thoughts! Thanks.