I would highly advise *against* poison and even glue traps. I have seen our hens gleefully rips an unsuspecting field mouse to shreds when it tried to steal their food one morning. It can also wind up poisoning other wild animals in the area. Any animal that eats the poisoned rats could be susceptible to the poison. Glue traps are also not the best option either unless well placed. There are quite a few cases of cats, owls, dogs, etc getting injured by glue traps from either curiosity or attempting to eat a trapped animal.
One of the best 'large volume' methods I have seen and used was one mentioned earlier. Large bucket or tote with a bar across it long ways and something over them to make rollers. Bait the center and have it designed to have enough rollers that the rat can reach from the edge to the bait. Tote is filled with water and high enough sides that the rat cant get out and drowns. Others probably get the hint and will still go for the bait and fall in. I got 5 field mice in one night but some people have claimed to catch dozens.