I brought my flock in to the brooder tonight after being outside for almost a half hr. Immediately, one of the chicks became aggressive with the rest of the flock. The feathers on her neck stood up, she stood still and made growling sounds. Is this the start of determining the pecking order, or was she just being plain mean? She isn't doing it now. My husband picked her up twice and held her upside down like you would a roo, but it didn't work… Please help?