Is it healthier to feed live rodents or frozen rodents to your snake?

right now i feed my snakes live with no probelems, thier healthy and alert. im thinking about switching to frozen thawed. but ive heard that feeding dead prey isint as healthy as feeding live, with dead prey they dont get vitamin B. but then again there are risks with feeding live. What i do to minimize the risk of injury is hold the mouse by the tail until my snake gets it. Both of them kill them finely. my brother is getting a baby red tail boa soon and hes gonna feed dead prey. what im wondering is is it healthier to feed live or dead prey to snakes? Thanks.