Just out of curiosity, which assortment and which hatchery is it? I thought it might be McMurray's straight run assortment but I don't see some of your rare breeds mentioned as possibilities.
The only straight run chicks I've ever ordered was in one order from Cackle many years back. I ordered 6 straight run Speckled Sussex and got 4 males and 2 females. I also ordered 6 Buff Orpington straight run and got 0 males and 7 females. Occasionally some hatcheries throw in an extra chick in case one dies en route and this extra straight run was also a female. What are the odds of that happening, 7 out of 6? Of the 15 pullets I ordered with the straight runs, 1 was male and 14 were female. That's more like what I expected.
You can never tell with straight run what you will get. Here's hoping you get the split you want.