Maggot farming

Maggot farming is the act of growing maggots for industry. It is distinct from vermicomposting, as there is no separate composting process going on, and maggots are used, which are distinct from earthworms, and which consume only flesh, not plant-based material.
Species used.
A variety of species can be used, including the black soldier fly. Due to convenience, fly species are often used which are indigenous to the area of cultivation.
Method of cultivation.
When using indigenous fly species, one tactic (employed by the Songhai Center in Benin) is to simply dump offal or meat that has exceeded the sell-by date in concrete bins. The bins are then covered with chicken wire to prevent any large animals from feeding. Then, flies deposit eggs on the offal and meat, and maggots hatch and consume it. After that, the bins are filled with water, so the maggots start to float (separating themselves from any leftovers). The maggots are then harvested and the leftover is discarded or further processed (e.g., bones can be ground to bone meal). An alternative method can be seen used more commonly in small scale applications, such as two trash bins stacked on top of each other. The bottom bin having a large hole cut on top, while the top having smaller, filtered holes on the bottom. Food (waste) is then inserted and left into the top bin, where the flies will lay their eggs and produce maggots, shifting and separating into the bottom bin. 
Use of the maggots.
The maggots are often sold and used as animal feed. In particular, fish, chickens, pigs, and ducks appreciate them. AgriProtein, a British company specializing in insect protein production, is pushing for more international business, claiming to hold the potential to shift the fish feed market away from energy expensive fish farming. They can also be sold as fishing bait. It is also possible to extract insect fat, protein (for human consumption), and chitin. AgriProtien claims to produce over three thousand tons of fatty-acid oil as a byproduct and sixteen tons of frass, or fly droppings per plant, which can be used as a valuable fertilizer.