You can always try the gold ring on a string test

I hear it's quite accurate. I tried it last year and was dismayed to find we had more roos than pullets...figured it was ridiculous and hardly a true test...but alas, it was right. Tried it with my current hatch and it seems to coincide with the ones I'd guess to be pullets by wing carriage, the way they stand, act, and the apparent (or not yet showing) tail feathers. So give it a try. If nothing else, it's a fun little test to distract you until you can tell for sure
Not sure...they look a little bit different than mine did....can't put my finger on it...but camera phones don't make it easy! They're definitely similar but there are other blue breeds. My friend got blue Australorps and they look very much like my chicks...so someone more familiar with all breeds will need to weigh in. Where did you get them?