What are the chemicals found in Pig Manure? Like humans, pigs are monogastric animals, meaning they have a single-chambered stomach. This is in contrast to ruminants, including cows, which chew on their cud. Pig farms generate a substantial amount of manure, just as human cities do. This manure is often digested in lagoons, where bacteria tackle the dirty job of breaking it down. Consequently, its composition is important to know when monitoring environmental effects.