Coyotes EAT domestic dogs, they don't consider it canabalism... If you get a dog, it must be one that is prepared for wild predators which have been killing for a living. Putting a family pet out there that barks is likely a death sentance for it. (I'm thinking you're well aware of that but I needed to say it, sorry)
A full sized door or gate where the coyote got through might be good, or something very solid there. If the coyote is quick enough, electric may not work. If they can get through before it zaps em... just depends on their speed. Coyotes are smart though, so maybe they'll see the wires and know it means electricity.
It MAY hesitated to come back since it was trapped IN your yard for a while too... they're not terribly fond of that, if it could have been terrified enough at that moment with something scary enough, that might have been a deterent, but it seems pretty unfazed by loud noises already so I just don't know.
A full sized door or gate where the coyote got through might be good, or something very solid there. If the coyote is quick enough, electric may not work. If they can get through before it zaps em... just depends on their speed. Coyotes are smart though, so maybe they'll see the wires and know it means electricity.
It MAY hesitated to come back since it was trapped IN your yard for a while too... they're not terribly fond of that, if it could have been terrified enough at that moment with something scary enough, that might have been a deterent, but it seems pretty unfazed by loud noises already so I just don't know.