Can I jump in here too?
I got six BO chicks on February 26. The (shady) guy I got them from is confident that pullets will have feathers over their backs much earlier than cockerels, and has assured me mine are all pullets. A couple seem to be bullies though, and flap their wings at and go after some of the others. They're slightly different sizes, so I'm thinking they hatched out kind of staggered and some are older than others. Some have combs that have pinked up and stood up a little, but not huge. Is this back feather thing a load of hooey?
I don't have a great picture of them right now, they never hold still!