one method that I was taught years ago with baits is to cause a competition in the population. one way to do this was to bait a area with grain then to make the bait hard to get to in the station. add the anticoagulants. only put out what would be consumed in the first couple hours of feeding another way is to make the bait only to be eaten in the spot, thus any sub dominates that may have beaten the dom there will try to eat and carry off before the dominate chases them off the food. another thing that would happen in large populous was the residence rats would die off and a new populous would move in and more activity would occur than the original problem. I remember the first time this happened to me I cleaned out the populous fast. things was qt for 3 or 4 days then all heck broke loose. the customer called me in the middle of the night with rats fighting in g the walls. the next morning I called Dr Mike Godfrey I knew him somewhat and he explained the reintroduction that was taking place. but instead of a controlled populous with the dominant rat maintaining control there was a populous of rats trying to take over. it has been 10 years since I have done any major rodent work so things may have changed but it use to be a 1/3 catch with traps and the rest of the clean out with bait, then when the new populous came in the traps again and work the baits. change up was done sometimes on a weekly basis. with a lot of baiting of grain mixed in.