The Tannery Terriers

In The Tanneries of Akorros, the rats are rife. They dig beneath the fences and walls of the buildings, chew the skins curing and foul them with their waste, dig nests underneath the compounds causing subsidence and collapse.
The people who live in the tanneries have it even worse. The rats steal their food, foul their water, gnaw through the boards they put down to protect themselves from the mud, and even nibble on people in their sleep.
No-one knew where they came from, but the workers started noticing dogs chasing among the back alleys, terriers with thick wiry coats and long legs, mud flying from beneath their feet as they scurried about chasing after the rats. And the rat numbers started going down in the areas where the dogs had been, and although the corpses were seldom to be found, a smell of roasting started to mingle in with the less pleasant odours of the tanneries.
Some of the premises started leaving out food to attract the dogs, and the workers would try to encourage them in, but the dogs were wary. However, wherever the dogs were, there always seemed to be one or more of the ghosts hanging about in the shadows.
And so the workers started leaving out food for the humans as well, along with clothing and blankets, and those premises which did so, found the depredations of the rats much reduced, and the tunnels the rats had dug into the enclosure sealed up again, and their profits rose. And they would arrive in the morning to find their enclosures swept, and the scraps of skin and flesh from the skins carried away. And the gulleys outside would be cleared of mud so they could flow freely.
But those premises which teased the dogs or chased the people, or worse put down poison, found their premises overrun with rats, and the rotting flesh would pile up in their yards - so much so that it must have been augmented with that taken from other yards, and their gulleys would be constantly clogged so that the overflows would back up into the yards forcing them to dodge puddles of blood and urine and soaking solution.
And so over time the superstition grew and the workers shunned anyone who mistreated one of the dogs or their owners, and any yard that didn't show its respect would find it very hard to keep their staff.