G'morning!
Kept back 18 so far in that age range. 7 are for sure cockerels so far and possibly more. 2 of the blues are clearly male already. Its a different bloodline on those and fairly easy to tell. On the blacks and whites though it will be until they are in the 6+ month range to tell on some. Those lines keep the huge rounded crests on the males and the whites especially have smaller combs. Not a single splash made the cut... On the buff, I'm using a new cockerel this year and the chicks have all been coming out clear so far. More problems with the underfluff being too light and skin color back to mulberry though. On the blacks I've only had 2 miscolored ones so far. Upon feathering out, they looked almost more like a dark partridge instead.
Don't worry Rilly...have you down for chicks for later this spring. Its way too cold for the girls to be laying much or to even ship anything yet. New baby is due any day too so that might put a hamper on things for a while too.