I do, when i buy them from the bait shop, they come in the styrofoam cup, with a plastic lid, and lid has air holes in it, and the sawdust is damp. Been told the damp bedding, retards their efforts to change into the pupa stage '' brown casing'' .
If you add water to the bedding, use Non-chloring water or you will kill them.
Best kept at 32 degrees in the frig.

Would like to hear more about what you feed them, and how long does it take them to turn red?