We get a few 1000 babies in every year and rehydrate them here when they come in.
When they come in they are between 5-7 days old some times older and have not been offered water when in Africa, so need to be rehydrated to get them on track.
We set them up in groups of 100 in large blanket boxes with about 1/2 " of luke warm water and let them soak for about 10 minutes. They will drink like crazy at this time, and plump right up. If you soak them more than 10-15 minutes then you have the risk of getting foul water as they will urinate in the water, or even a little feces from digesting their yolk.
Once they are rehydrated we set them up on bedding with a water bowl in shoe boxes so they can explore and drink as they choose.
One very important note is not to ship a baby when it has just been rehydrated as they will urinate a lot and that can cause a very high amonia build up in the box and kill the snakes. Give then a day or 2 after soaking before you ship them, and you are good.
Hipe this helps.