I would make it taller with more shelves instead of wider so the shelves don't sag. There was a guy selling 10 tub corn hatchling racks on fauna for like $50 or something. I think he used hardwood for the sides and routered in grooves that held 1/4" pressed board. Each one held a tupperware sandwich box. I would make something like that, maybe 15 high x 2 wide, or 10 high x 3 wide. You can always order this if the hatchlings won't be in there for more than a couple of months.
http://reptilebasics.com/Interdesign...k-p-16255.html