We decided to use air rifle tactics with night vision to quickly reduce the numbers of rats at the property, we then flushed rats from their burrows where they were quickly dispatched by trained dogs and finally finished off with burrow baiting. We physically accounted for over 100 rats without counting the numbers which the posion took.
It is important to keep an open mind when targetting rat problems. Rats are quick and effective at reproducing, they quickly learn to evade harmful situations and often harmful posion baits. You need to be one step ahead to deal with a problem.