Hi My 10 month old collie cross puppy, has changed over the last few months and now seems to be scared of strangers. When she was younger she was the opposite, very social and always wanting attention from strangers. She was socialised well from a young age. In the last few months her behavior has changed though. If anyone approaches her she will back off quickly and not go near them. Occasionally she will even bark or a growl a little bit if approached (she would never bite though and is very gentle). I'm not sure what has happened, as she hasn't had any bad experiences that I know of. Is this normal? And how can I fix it?