We used a barrel with a gravity fed cup waterer attached about 6-8 inches up from the bottom. We kept a lid on it to keep birds, mice, and other critters from accidently ending up in it. We usually fed 4-6 pigs at a time, starting at about 50 lbs, and butchering at 250-275. Unless you anchor the barrel, you'll probably need to fill it every day to keep them from moving it around and turning it over as they get closer to being empty.