
We have 2 Patterdales and still have rats - that is the joy of living in the wilds of Norfolk.
Even though the Patts catch many rats we still had them around the stable ( horses, goats and sheep) and the chicken coop where the Patts are not allowed to go.
We have a contract with the 'Rat Man' to come round every few weeks to check and top up the poison boxes. The boxes are dog safe and he is very careful where he places them in areas where the dogs cannot reach. Even if they did manage to reach a box it is doubtful that they would get into it assuming they would want to as it is not made to appeal to other animals, and the boxes are very secure ( unlike the DIY boxes you can buy)
The Rat Man always tells us exactly where he has placed the boxes and in the 5 years he has been doing this we have not had any dogs interested in the slightest with the boxes and our stables and out buildings are clear of rats. The final straw cam 5 years ago when I went into the stable at dusk and stepped on a rat and another ran over my foot - that was it and war was declared.
We have never seen any dead bodies around as they tend to die in their nests, but at the beginning we interrogated the Rat Man about what would happen if the dogs found a rat that had been poisoned and he confirmed that the amount of poison in a rat would not cause a problem with a dog, but it was unlikely they would see any bodies, and he was right.
My main problem is rabbits that have been poisoned by the farmer in the fields near our property, they tend to just lie around to die instead of going underground.
We got 3 feral cats a few years ago to try to keep the rats down, but we ended up with 3 very fat feral cats that were so surrounded in rats that they didn't need to chase around for food so became lazy sleeping all day and not getting rid of any rats apart from the few they used for food.