I have seven 2-week old chicks. I've caught two of them sparring with each other twice now. One I have suspected was a roo since it was maybe 4 days old. It's shanks are very thick and it just acts cocky. I know pullets will spar but these two seem to mean it, they'll stare each other down, peck, kick, jump and end up winded. Are there any behaviors that indicate sex this young?