If your idea is to get a snake because it eat year round it might not be the best idea, there is absolutely NO GUARANTEE that any snake will eat year round, slight change in the weather, husbandry etc can lead to a snake missing a meal or two or even more.

I have Bulls, Milksnakes, Carpets, BP and a Blood and I can tell you that aside from the BP all the others are what I call garbage disposal IF their husbandry need are met, however even than they might still miss a few meals, keep in mind that if they were in the wild they would probably not eat as much as they do in captivity.