Jen, i can't be of much help, but thats like my older dog, he seems to like hate them with a passion or something, most dogs want to chase them for fun and play, like josie, but rufus doesn't. He caught one once (lucky me the owner was right there..it was there yard) and he jumped on in and started to bite it, but i grabed him before he could do any damage. Another time (my neighbors cat used to come over and sit in front of him (he was on a chain back then) and she would clean her self, just tanting poor ruf, hes strangling himself trying to get to her, being a strong dog her broke hes collor in half and jumped after the cat (who i must say jumped atleast 2 ft once she saw what has happened) she darted under a fence and up a huge tree, and didn't come down for the rest of the day, ruf jumped right overr the fence which came to a bit of shock to me cause it was very high..then once he realized she was gone, he took off for his little night adventure. I still wonder why he hates them so much, but he hates milk men (used to..) also, i think one hit him with a stick once..The cat never came over again..
Can anyone elses dog seem to know the milk or paper man from other ppl?? It seems weird but he'd bark only at them, no one else.

Anyway, sorry i wasn't of any help just wanted to say something similar has happened to me