Yep, always freeze what ever substrate you are going to use, before you use it. Weevils aren't a good thing to propagate, no siree. Been there, done that. I like the shoebox individual method or even small totes.
I will have to go back and see the other methods you are using on here. Mine eat potatoes sliced in half or carrots and fortunately with the dry climate here I don't have any mold issues.
The worms begin so tiny that your best bet to know if they are there is to just take a large spoon and scoop up some wheat bran (or whatever you are using) hold the spoon still and look for movement. If the bran seems to fall or move then your eggs have started to hatch.
I am trying a new idea and keeping my worms in the chicken coop out of the way of the hens. It is almost always warm in there and the beetles seem to like it in there. It keeps the stinky worm smell out of the house.
I do have a few boxes in the house to harvest pupae for the next batches but I am going to put an old "gorilla rack" out in the coop for the boxes of worms. Time will tell if works best or not but at least I will pay attention to them in there as I am in there everyday. In the garage the poor things got forgotten for months at a time and survive by cannibalism. They make it through winter, summer and no moisture and still survive. I love these guys.
With any attention you'll have nice fat wormies to feed all the chicks.
Has anyone posted about drying the worms for later? I'd like some info on that. Thanks