denise, sorry to hear you have to move your bees. what i would do is move them late in the day, at dusk, to get as many foragers as you can in. screen them in, then move them to your garden. you can leave the screen on overnight, but go back early in the morning and remove it, they will pour out of the hive and reorient. like others said, feed if need be, and give them water. there really is no need to keep them locked in for 3 days.
keep us posted on how the move goes for you!