I've kept Brahmas for years and have only ever used normal chick starter, and they have grown into huge birds (Admittedly they have huge parents and free range from a few weeks of age).
In Britain only special couriers are licensed to ship live organisms and the cost is prohibitively expensive, so it very rarely happens. If the chicks were young and heat requiring, the external temperature low, the chicks not well, inadequate air supply, delayed shipping, or any combination of those factors, then survival through the post may have been compromised.
Sorry to hear that you have had such bad luck.