the best red wiggler factory I have ever seen was under a large rabbit cage. My grand father had a 8' cage divided into four sections, the floor was a open heavy mesh. And the ground had a 2x10 sorrounding the cage. Of course all the rabbit poo fell to the ground and the wigglers were packed in there. All he did was raised rabbits and i collected the worms for fishing and to sell to some local baits shops. I have no idea how many where there, every summer I would by a case of 2500 cups and lids and package a few hundred a week. 2dz per cup and never got low. Well that was long ago but sometimes I miss the money.