The only time I've ever hear of cannibalism among corns was when they are very young and it's a rare ocurrence (sp?). I wouldn't personally keep multiple young corns together and there is always going to be things that are harder to track if you're keeping snakes in the same enclosure. However, I know that up at NERD they have some of their adult corns (5 or 6 I believe) in a large cage and they seemed to be doing just fine.