You want them to eat at least 3 to 5 times successfully and consecutively for your average hatchlings, those that are very small to start with below 40 grams I recommend 7 to 10 feedings at least.
Thing you need to know prior to shipping are, how to pack properly and use the appropriate material, you also must know the temps at origin, main hub where the animal will be from about 10 pm to 5 am and destination where the animal will usually be delivered by 10.30 to noon.
If the temps are extreme you may elect for shipping to a fedex staffed facility for customer pickup or delay shipping.
For the rest you can look here and here which will give you important shipping guidelines.