I had this same behavior out of my 4 two weeks ago at our annual Fall Festival party. Family and church friends all come out to the decorated farm and have a cookout and the kids get candy treats and hotdogs and haunted train rides thru the woods and walking back out because once again I've failed to be SURE the train will run THIS time.
Anyway, a lady brought her little dog along 
and my four goats could have eaten it, but since the are prey animals, not predators, they went into the defensive posture; even though they were BEHIND defence!
Stayed that way 'til the lil doggie went away.
sounds like fun, but the goats probably were not too happy with that nasty predator around, he looks vicious...:O).......boooo on your mohair, nohair but you got a sense of humor. More important than hair...