I really hate feeding frozen, i prefer to feel Pre Killed prey to all my snakes

I want to make a gas chamber but how would i go about doing this ?

Would i just need to buy a cooler, dry ice, and a container to put it (the dry ice, so that the rodents connot get to it) in and just add rats and close the lid ?

Im thinking it cant be too complicated

i would need enough dry ice to knock out small-medium rats and adult mice, how much do you reccomend and is there a reccomended cooler size ?