my year old Cairn has been a lovely well behaved dog but in the last month or so she has started barking at other dogs when we are out walking. She walks really well on or off the lead but if we come across another dog she gives chase and starts barking. this is a regular occurrence now but she doesn;t bark at every dog, and there doesn;t seem to be any pattern to it.
any suggestions on what i can do? i put her back on the lead when i see other people/dogs approaching and always hold her back and say no in a firm low voice as soon as she starts, but it seems to make no difference.