So it obviously would be safest to cover the entire thing with hardware cloth, but whether it's absolutely necessary depends on your predator load, predator types, budget, how you manage your set up, tolerance for loss, etc.
I have hardware cloth up 2' and out 2' in an apron, over chain link. Netting on top. It's less secure than what many people have, but my run is 20' from my living room and I can clearly hear the chickens from inside the house, and I'm home 90-95% of the time, so I rely on myself and hubby as a level of protection for the chickens as well. Coop is also fully enclosed by the run and closed up at night.
I have hardware cloth up 2' and out 2' in an apron, over chain link. Netting on top. It's less secure than what many people have, but my run is 20' from my living room and I can clearly hear the chickens from inside the house, and I'm home 90-95% of the time, so I rely on myself and hubby as a level of protection for the chickens as well. Coop is also fully enclosed by the run and closed up at night.