One the most effective method methods of rodent control is the Rat Zapper (ratzapper.com). It is a little electric chair for rats that runs on C batteries and can zap rats for months on one charge. I have zapped 7 rats in past 2 weeks alone. Rats and poultry go hand in hand, so I am always trapping around the coops and in the barn where we keep the food. If you are really serious about rat zapping you can purchase multiple units and a remote that alerts the user when a rat is zapped. I learned about this amazing invention from my mom, who is an expert in all things varmit related.