To my knowledge, cooking them would destroy a lot a nutrients in them. On top of that, snakes are designed to eat raw meat, so why risk any issues that could arise if fed cooked prey? If they would even eat it. You also should never have rodents in anything you would cook in or eat out of, since that could make you sick. So cross-contamination would be another reason not to. @t_h_wyman might know more, but over all I think is basically a common sense kinda thing. If they are designed to eat one thing and you feed them something they aren’t designed for, then problems could come of it. It is like people that try to make their cats vegan.