I would think a Great Pyrenees would hold its own against a group of coyotes. I wonder if the attackers were dogs.2 of my parents 3 dogs got into it with something (most likely coyotes) early yesterday morning and they got tore up pretty good. They're usually pretty smart and have ran off more coyotes than they've fought with, but something didn't go their way this time. One of them (female Great Pyrenees that is a sister to ours) got her hind legs bit pretty good and dad has said she's really sore, but has gotten up and roamed around some. He had her setup in a warm dog house, but she left sometime this morning and he found her laying down out in the pasture. I'm not sure if she was leaving to go die somewhere or what. He said she didn't like it when he tried to pick her up and move her.
Might be time to lock the dogs up for a bit and go after the attackers.