If you want to control the coyotes, get an Irish Wolfhound...
They are the largest dog and were very effective at controlling the wolf population - they almost made the wolf extinct in Ireland when the farmers got them...
We used to have a black lab mixed with a wolfhound...
That would do it if more folks had one, most dogs will hid in there dog house if they are smart, a pack of coyotes will take most dogs out or hurt them badly, I have seen three on a dog and was pulling him apart