Thanks, Lynn and Heather, for the info and PM

Lynn, I "rescued" them from an inept owner on a local online auction. They were originally used as educational tools at a kindergarten but sadly not very well cared for.
Heather, I can ring the pet shop/ BioSuppliers and see if they sell pinhead crickets, if they do, I'll order some and give the glass bowl method a whiz sounds a lot less stressful than fruit flies to be frank!

I actually feed them in a separate, smaller tank so I can get an idea of how much they're eating. Is this ok to do? It minimizes the tank cleaning I have to do lol.

I have occasionally seen them soaking themselves... occasionally mind you, so not very often. Do you think they're not hydrated enough?