I am coming to this late,but most hatcheries only guarentee a 90% accuracy rate,BUT while Cackle goes into detail about different breed ( they have a 90% guarentee,but under each breed they discuss that some are harder than others) they discuss some breeds consistently are only accurate for...
A lot of their sales are straight run which should be approximately 50 /50 but from hatching here at home I've had 1 cockerel and 5 pullets or another hatch was 6 cockerels and 1 pullet so straight run is a crap shoot.. I get their flash sale alerts etc and 95% of them are straight run