I have a 3 year old Springer Spaniel over who over the last 3 months has started having sudden bursts of aggression for no apparent reason. He is an otherwise friendly dog and our other springer is not like this at all. Having a young child too though is a bit of a worry. I have owned lots of dogs over the years, many of them springers and have never encountered this problem before. Could it be something we are doing wrong or could it be an illness? I will be taking him to the vet this week but any advice or similar experiences from people would be welcome.