Wow! Up to 12-20,000 is roughly 2 square feet? That's a thick carpet....and you don't note they get too hot on top of each other like that? If that's what a good bin looks like, mine is lacking, as I have about 5 thousand in 5 square feet. I need to get them producing to be so lush. You sure do know what you're doing. All the best-Hmmmmm....I really don't know, people have asked that before and I can only guess. Maybe 12k-20k? Again, that would just be a guess.
outside on the porch.
I know I've had at least two beetles morph out. I saw them for a few moments and they promptly dove in the bedding and I haven't seen a one since. But I see lots of pupae so I know soon we'll have beetles in numbers enough to get down to business! Even a lot of the mealies dive for cover when I open the bin and I haven't even started harvesting yet 
