Maes et al. (2019) on Intensive Pig "Farming"

Dominiek G. D. Maes, Jeroen Dewulf, Carlos Piñeiro, Sandra Edwards, and Ilias Kyriazakis, "A Critical Reflection on Intensive Pork Production with an Emphasis on Animal Health and Welfare." Journal of Animal Science 98(Suppl. 1): S15–S26, 2019. 

• As the title suggests, both health and welfare are examined in this article, though the bullet-point "summary" here will focus primarily on the welfare discussion.

• "Improved animal nutrition, feed efficiency, health management, environmental control, reproduction management, genetic selection for better performance, and consistency of product quality and delivery to the marketplace have been the main objectives in the development of intensive livestock production [p. S15]."

• Intensive (indoor) pig farming brings many health benefits for the pigs relative to alternative husbandry methods, though often with the excessive use of antimicrobials. Early weaning of piglets, however, heightens stress and also contributes to health problems. 

• The assessment of pig welfare has made significant strides in recent decades. The authors employ the EU-initiated Welfare Quality® assessment [pdf here; 21-minute video here]. 

• Among the pig welfare problems that occur with intensive production are painful tail docking and teeth clipping; little room (indeed, sometimes confinement in tiny crates), little environmental stimulation, little opportunity to engage in normal behaviors such as rooting or nest building; and flooring that is slatted or concrete and contributes to lameness and other health problems.

• The authors offer many suggestions to improve the health and welfare of pigs, such as improving the flooring and enriching the environment, and reducing the painful (and non-anesthetized) surgical procedures. More space per animal (and fewer crates) are high-priority needs.

• How about more transparency?: "informing the public properly about the health and welfare of the animals, and providing greater transparency in farming operations, eventually by providing (digital) visual access to the animal facilities, might be required [p. S22]."