The new box has about twice the floor space, but lower ceilings, so the mesh top will be staying on.
The chicks are growing so fast they've already outgrown their first bin. The only larger one I have isn't as tall. Since I don't want them hanging out on top of the feeder & waterer (read: pooping in the feeder and waterer), the low ceiling is probably a good thing.
They're psyched about the extra room.