From my personal experience, Emu's are stronger in numbers. I've had juvenile Emu's gang up and chase away dogs before. However, Emu's are more bark than bite. I've never had one mean enough that I couldnt stand my ground to, and it wouldnt run the other way. If the right predator comes up, then all they can do is run. Despite the talk of them having such lethal kicks...they really don't. They mostly just run over top of smaller animals they consider a threat, and trample it. They're best defense against predators is out running them. The only Ratites that i've known to literally kill or severely injure anything with a kick are Ostriches and Cassowaries especially. But still, I wouldnt worry about foxes taking down a juvenile Emu. A bobcat...yes