I thought of that tooCome this winter, they'll have to come in...or I'll be seating each bin in a pit surrounded by horse poo for the warmth! Not a bad idea, considering how allergic I am to the bedding and worms...
Has anyone ever tried the 'classifying' screens they use for evaluating dirt, to sort their mealies by size? It's kind of like that old toy where you shook and shook to get all the teensy balls down to the bottom....
ETA: For debugging substrate, I'll go with Use The Sun--which means you put your bran in a black plastic bag and lay it on the back ledge of your car, with the windows closed, on a hot sunny day. Anything that survives THAT, well....it deserves to live, right? (Ave temp in my car in those circs is 140F-220F, depending on outdoor temps and sun intensity.)