so they'll send the kids in to bring back the food...........A quick search tells me that the size hole a mouse can fit through is limited by the width of their skull. Apparently adult field and house mice have skulls that range from 2-2.2 cm wide.
1cm=0.394 inches
Looks like you're safe with 1/4" hardware cloth.
bahahaha..........sorry Blooie I couldn't resist