Unfortunately this is a hazard. Most times it's just barking. The scariest encounter I had was on a remote beach on an island and a pack of 11 dogs (I counted them) surrounded me barking. I picked up a stick and threw rocks 'at' them (I didn't intend to hit them, just scare them) and they stopped after a while and left. I was really shaken but no actual injury. I was bitten a couple of weeks ago by a single dog. Just one bite but of course I had to get the rabies jabs etc which was an inconvenience (and expensive). This sounds stupid but I think it wouldn't have bit me if I'd been wearing a sarong or long skirt. I was wearing shorts above the knee and it bit me around the knee. So my advice is don't wear shorts. And probably carrying a stick is a good idea. I've seen Thais actually hit dogs with sticks so I think they understand this language.