Last weekend (Nov 14 2009) I added 1/2" x 1/2" hardware cloth on the whole run. We have raccoons in our neighborhood and if they can get to the chickens they will kill the whole flock in minutes.
Omlet, the company that makes the Eglu Cube, is in England and apparently they don't have raccoons, just foxes, so the run has 1" x 3" wire on it. That's not small enough to keep out a raccoon hand, which is why I spent 5 hours putting the hardware cloth on it!