I would think that feeding the scraps to the BSF would lower the efficiency. Adding steps may increase the concentration of protein per gram (scraps vs BSFL), but the overall efficiency would drop as you would have frass and larvae. I don't think the chickens would eat the frass.

Of course, you would have some compost (but less than vermicompost) to use where you wanted to, as opposed to just where the chickens drop it.

I would do it, just because I love all kinds of compost.

I don't have anything against compost tumblers, but the extra work and equipment chafes my permaculture streak. I've already got enough chores to do. Building another contraption, maintaining said contraption, loading it and rotating it just seem like more energy than I'd get back from larvae or faster compost.

I'm progressive in some areas, but when it comes to compost, I believe in just leaving it as simply as possible. Dump stuff in until it's full. Then dump stuff into another bin. When the first bin is done, clean it out and use it. I do try to keep my additions to the pile balanced via green/black/brown but that is the only effort I put into it.

Eric --- It would be worth a loss of efficiency if we ended up with extra protein --- protein is the hardest thing to "grow" for your chickens. I'm still on the fence, though, about whether this would work or not....

Danny --- I know what you mean. That's the way I tend to do compost too, except that I can never wait until it's really done so often end up using it as part of kill mulches or new tree mounds.

Anna--I think i recall you saying in the past that you don't have a lot of food scraps. So the question of efficiency would definitely be a concern. Plus, like you said, patience is a virtue--so if you try it, be ready to stick it out until you're sure it's not worth it. Years ago I tried my first compost bin from a plastic garbage bin (75gal size?) with holes drilled in sides for ventilation. Little did I know that the gross, fat, black caterpillary things soon crawling out the holes were BSFs. I was so grossed out that I abandoned the whole project. (Did i mention that both my parents are entomologists, but some buggies just catch ya on an "off" day?!) Our family has lots of scraps, so I will absolutely try it again with a tumbler when I get chickens again.

The food scrap shortage is precisely why the bin would have to be ultra efficient to make it worth our while. Because that would mean stealing scraps from the chickens....

I suspect why the tumblers "work" so well as black soldier fly bins is because they tend to not be well enough drained/aerated, so scraps ferment before they rot. Which means that something even simpler that's similarly water-tight would probably work as well --- maybe even a raised tupperware container with holes in the bottom just the right size.

We all have our "ugh" moments, especially when things take us by surprise.