if I'm thinking right, when feathered in in a few weeks, cockerels will develop feathers that have a "barred" pattern while pullets will remain black. I have absolutely no experience with black sex links though, so don't take my guess as an expert opinion
Ok...because none of them have any dots on the head but there is one that is distinctively larger and has the larger thing on the beak sorry so new to this I don't know the correct lingo. Also it has a bigger feather area than all the others...so just didn't really know if they were all males or females...we are extremely confused they are 5 to 6 weeks old. Here some more pics.