That’s very interesting and don’t recall ever reading about large scale “rodent farming”.
How do you think petco gets all it’s mice and rats for reptile feeding they don’t catch them off the streets. More like breeders with a couple.hundred animals not the giant feedlot set ups with tens of thousands of birds. The concept is the same though. Dense cages with same sex offspring in a cyclical feeding and breeding operation. Mice are not all that cannibalistic if they are all same sex and aged. Rats are harder to breed they will eat each other so individual caging is needed stacked and packed is the way to go. Just like chickens which are dense packed in individual cages they can barely turn around in. Same concept same reason for it chickens are cannibals.
I helped a guy get into business many years ago raising rodents for the zoos. He had a really great business until he decided he could wipe out all his competition by starting a price war. Epic fail!!! North Texas Mouse Manufacturing -— I still have the t-shirt.