You could do an order for the amount you want but some might include male chicks to keep the shipment warm from what I read.
I would either go to the feed store and pick up the amount of chicks you want. Or just do a min( 25) order of some chicks you would like and sell the extras you didnt want to keep. I did this and found that there was a big demand and didnt have any trouble selling my extras, although I did raise them past the brooder stage, 5 to 6 weeks old.