I run with my 2 dogs off leash. ( I have them on shock collars).
Anyway, 3 wild dogs came at them. They just popped out of the woods so there wasn't any warning. My little dog (50 lbs) was farther away and took off. My bigger dog (65 lbs) was screwed. I feared the worst as it was 3 on 1. However, my dog is from the poound so I guess hes' got some experience. The first dog charged him. My dog stood his ground, grabbed it by the neck and threw it to the ground and pinned it there. The other dogs stopped coming at him and the dog pinned to the ground got up and went away.
These dogs came barknig at us the next time saw my big dog and just turned away. So whatever you do don't act scared if you can. The pretending to pick something up is something I haven't heard of but I could see working.
***
On the other side of the coin, my same big dog will bark at people on my property. One day I was going to the car and didn't have him on a leash. A construction worker next door happened to be coming out at the exact same time and walking on my property to his car. My dog takes off barking and running at him. I'm yelling and running at my dog. I figured nothing would happen but my dog acts so pissed at the randoms on my property it was just a situation I had never seen before.The guy just stood there and the dog stopped right before he got to him. I apologized profusely. The fact I was yelling at him may have had a small part of it but I'm not sure. But I said to the guy,"If I was you, I probably would have been winding up to kick the shit out of the dog". Or turned and ran. He pointed out turning would have been the worst thing.