I've got a corn snake jus over 3 foot , im currently feeding Him/Her Just 1 , One Day Old chicks every 7-10 days and it seems to be doing fine . I tend to feed it chicks because there cheaper , as adult mice are £1.50 , and One Day Old Chicks ARE ONLY 7 PENCE!! . The chicks are also a little bit bigger than the mice, I hope this helps