The first picture in row number two-that is a cockeral. The others i think are pullets. If you can keep a rooster where you live, you should keep him (if you don't already have one) because a rooster is a good protector of the hens.
Sometimes it is hard, but rooster's have sickle feathers-long pointy feathers on their backs, and hens don't. Often you can kind of tell by the way they stand-tall and straight. Also their feathers may have a shiny green tint to them.