The deal seems to be this:
The female should be at least 200 grams in weight, probably about 2 years old. Size has a lot more to do with it than age beccasue you don't want her to get eggbound. Males can be smaller/younger.
If you want them to breed, you can make that more likely by brumating them, but that does not guarantee that they will breed, nor does it mean that they won't breed if they were NOT brumated. That last point wasn't made real clear in the Kingsnakes.com breeding page, and I thought that they wouldn't breed if they weren't brumated, but that turned out not to be the case.
There is a specific time of year that corns are more likely to breed, late spring/early summer, but I have read that there have been some ongoing experiments with temperature and light exposure to see if these things can be changed to manipulate captive breeding.
