Without sexing them professionally they have another method that is about 90% accurate. They are barred rocks, I breed them. At a day old you look at the spot on the head. If it is tight and close together and bright then a pullet. If more spread about on the head then is a cockerel. Only 90% accurate but I would say that the one I think is in the front is a pullet.
I've heard of people using this method, but I've personally found it to be an inaccurate way of sexing chicks. This is why I am basing my opinions on the wing feathers, as it is quite simple to sex a bird as these feathers are coming in.
I agree i was basing on the fact of ohw young these ones are. here is a pic of one of my pullets. feathered great. cockerel is about same as the ones in the pics but they are same age.3 weeks.
And these are a bunch of mixed chicks but here are pullets and I don't know if the cockerel is in there or not. I marked his head with blue water marker. Not the best pic.
I only breed Dominiques and I base my opinion on the leg shank color along with the solid spot (not scattered) on the head as being a pullet, this was my basis. However looking at the pic more its my opinion that they look more like Barred Rocks.