I just purchased BSFL from the same people i purchased from through amazon before (because the supply i got from the reptile show all mutated into adults within one to two days of purchase).
The shipment sent to me had very wet soil, and the BSFL were plump but mostly white skinned. However when I feed them to Kohaku chai they aren't moving (unless it is so slow i can't see it) , even though they are medium sized and not turning dark yet. There are 500 in this current container.
Can too much water in the soil have 'drowned' them in transit to me? The first shipment from this supplier was very good quality so I find it unusual that this happened on the second shipment.
I've received BSFL with damp soil but not wet. I would take some out and dry them/warm them a bit and see if they react. If they don't wiggle around then they probably aren't good anymore and I would replace them. They tend to be pretty wiggly when they are healthy.