When we were kids we raised Arabs. We had one stallion that ran with 4 mares and their foals. We found NUMEROUS dead stomped dogs, coyotes and foxes in our horse pasture. I think it was the Stallion and the lead mare.
They just did not put up with any canine or wild animals near the heard.
I don't know if it was about protecting the foals or the heard in general??
But those horses has over 100 acres to run on too.
Just saying that some horsees can and do protect themselves. Not that all will or can but ours always did. My horses I have now don't even PLAY when the dogs mess with them the horses
Stomp the ground right by the dogs like "Yes I CAN STOMP THE TAR OUT OF YOU IF I WANT TO SO HIT THE BRICKS" AND mY DOGS (bulldogs) GENERALLY TAKE THE HINT.