USDA is experimenting with Sodium Nitrite as a poison. It kills fast and does not affect other animals that eat the remains. It is used in food preservation such as sausage, etc. The problem is...figuring out a way to make a container with the bait pig accessable but not coon, bear, etc., accessable. We have had the biologists here where I live discussing it with us. It is being worked on in Alabama and Texas as we speak. Sodium Nitrite is being used in Australia and works well. It does not take much, is inexpensive, and does the job. Australia was using Warfarin but it was too cruel and the poisoned meat killed other critters eating it. Where I live there are scads of pigs. My hunt club borders a National Park and pigs are a real problem. Even using traps, dogs, shooting, and even poison will not get rid of all of them since they reproduce rapidly and they come back. You need to eliminate 70 percent of the population each year to keep hogs at a level state. We have USDA shooters and trappers on the National Park trying to keep the population down now.