Chances are the yorkie challenged the other dog first, with just a look, things we as humans don't notice. Since the yorkie got the worst end of it, it may not happen again.
I'm thinking it was more of a possesive issue than a protection one.
It could be that the younger one is just now getting old enough to want to try to dominate the older one and the older one isn't going to take it.
Heres a TIP
I don't know what you told them in the ER but most ER's are required to report dog bites and they will go on record as being vicious. So if there is any way around it, try to report it as something else. A nail puncture or anything other than a dog bite. some cities have a three strike rule for dogs. |