BSF is Black Soldier Fly larvae
Cocci... two best things to do... cull heavily - eliminate any birds not resistant. Treating for prevention is not the answer - heavy culling is.
And evaluate your management practices. No chicks where you have damp conditions at all or any unsanitary conditions. If you're having a problem at all, consider raising chicks to get them off the ground and then a gradual introduction of dirt/sod to their raised coop.
Yes fermented grains will help overall health. But like most "natural flock prevention measures", it will not solve a current problem. Once your current penitentiary is solved, fermenting and other positive health measures (such as wood ash for dusting for mite prevention) can be great.
First step is to solve he problem... then prevent future problem.