Note that this is different from a EPA's definition of a confined animal feeding operation which is an animal feeding operation larger than a given size.
Asphyxiation is the deficiency of oxygen in the air, making it difficult or impossible to breathe.
Ensiling is a process by which fodder or feed is stored in a silo in order to be converted into ensilage, a more succulent feed for livestock. The silo air access to the structure to encourage fermentation. The lack of oxygen and acid conditions prevent spoilage and preserve the value of the stored feed for several months. Farrowing is the stage in swine operations during which the pigs are born, and kept until they are weaned from the sow. Finishing stage in swine operations is the growth stage leading up to market.