She did this for years and they were terrified of her. 70 pounds of lab coming at you in the dark forest at full speed would readjust your attitude right quick.
I have seen her take off after them and from the sound of the coyotes screaming they cannot see her in the dark and she seems to knock them over or possibly knock them into the air. Never heard that sound from a canine before. She comes back with spittle on her head and a smile on her face.
I have 70 pounds of black/brown brindle KNPV bred Dutch Shepherd and watched as a pack of six coyotes came out of the brush to almost kill her but for her quickness and intelligence. She got one of them good, but I'm not taking that chance with her life again.
One dog against a half dozen or more coyotes is not a fair fight. It's better to call and kill them to keep the numbers under control. At that point, a dog has a prayer of keeping its territory as it gets older and the eyes grow dim. Coyotes multiply rapidly, as much as 4X per year. They learn fast and adapt to pressure. So I think you are taking foolish chances with a dog that would give her life for you. As things are now, I wear a sidearm when I get far from the house. When it comes to coyotes, I don't want even close to a fair fight.