Well how we did it was used the 1/4 for the top and for the food hopper we used the 1/2 but we took some PVC pipe and put it around the top and left like 2-3 inches on the bottom for them to be able to eat. And since there is always going to be food in there the babies are not gonna squeeze through there and push their way up to food. Plus we made a top for the top of the hopper so it could be sealed off.