Intensive animal farming or industrial livestock production, also called factory farming, is a modern form of intensive farming that refers to the keeping of livestock, such as cattle, poultry (including in "battery cages") and fish at higher stocking densities than is usually the case with other forms of animal agriculture—a practice typical in industrial farming by agribusinesses. The main products of this industry are meat, milk and eggs for human consumption. There are issues regarding whether factory farming is sustainable and ethical.