We and hundreds of customers and colleagues do occasionally find the need to house more than one corn snake per cage, but even when precautionary measures are employed, there is no guarantee that one or more cage mates will evade injury or death from feeding confusion by one or more snakes.
Precautionary measures that reduce the possibility of cannibalism among communally housed neonatal corns includes (but is not limited to) feeding them separately outside the community cage and thoroughly rinsing each snake with slightly cool water for 30-60 seconds before reintroducing them to the commune. Regardless of visual appearance – to a neonatal corn, anything remotely tasting or smelling like food is on the menu. This includes your fingers, so never allow prey OR predator smells to be on your skin or clothing before handling any snake.
Instances of injury from mistaken identifications like these are common among snakes since it’s virtually impossible for any snake not to have rodent odors on them after eating, and because a corn snake’s sense of smell is so utterly acute. I estimate the chances of cannibalism, even after employing such precautionary measures as thorough rinsing, to be 1.5% to 3% (based on customer testimonies and my personal experiences), but community housing is still ill-advised.
Many times, I’ve witnessed attacks by corn snakes when suddenly awakened by room lights coming on, jarring of their cage, and just from rodent smells in the vicinity of their cage. That said about hatchling corns, I have never witnessed a corn snake over 30″ (76cm) long being seriously injured or killed by a cage mate. At that size (and larger) initial feeding responses that cause the attack are usually halted when the power of the attacked snake is demonstrated.
I think the odds of serious injury or death from larger communally housed corns would be much less than 1%. It is contrary to the basic instinct of corns to relish eating other corn snakes, but survival instincts being as strong as they are in most animals, anything is possible. Therefore, housing them separately is always advised.