Heart-Centered Humans for Animals' Rights and Protection
Sows (female pigs) are artificially inseminated 2-3 times a year, and kept in gestation crates that do not allow them to turn around. After 3-4 years of this barbaric life, they are sent to slaughter. 
Pigs excrement falls through gestation crates' slots into cesspits below the crates. Pigs are not able to escape the highly toxic stench of their own waste, and most suffer from severe respiratory ailments. 
Highly intelligent, sensitive, and social animals, their suffering is unimaginable.
About 1,000 pigs pre hour are killed at a typical slaughterhouse, making the process quite gruesome for the pigs and workers. Although stunning prior to killing is required by law, the sheer volume of pigs makes the stunning process less-than perfect, and many are conscious when their throats are slit, and still conscious when entering the scalding tank where they drown . Pigs are very large, sensitive creatures who are easily frightened. Electric prods and rough handling are used to get them through the slaughter lines.
Some slaughterhouses use carbon dioxide (CO2)
to kill pigs. CO2 causes enormous pain to the animals, as their lungs literally 'burn' up, taking about two minutes to die .
1. Philpott, Tom. (2013, July/August]. You Won't Believe What Pork Producers Do to Pregnant Pigs. Mother Jones. www.motherjones.com/environment/
2. (1.) Philpott.
3. Gay, Lance. (2001, Feb.). Faulty practices result in inhumane slaughterhouse. Organic Consumers Association. www.organicconsumers.org/old_articles/ irrad/insensibility.php
4. Akbar, Jay. (2015, Feb. 17). Revealed: Disturbing footage of pigs struggling to breathe as they're killed by CO2 stunning method being used by supermarket abattoirs. www.dailymail.co.uk/news/article-2942309/Disturbing-footage-pigs-struggling-breathe-killed-CO2-stunning-method-used-supermarket-abattoirs.html
USDA-APPROVED HIGH-SPEED SLAUGHTER (3:41 min.)
Pigs are raised in warehouse-like structures that house up to thousands of pigs each. The best circumstances may allow pigs to be crowded in separate pens. They never touch the ground, see sunlight, breathe fresh air, or have the chance to live their lives according to their natural instincts.
SECTION HEADS ARE ALSO LINKS TO PAGES
Happy and Free in an
Sow confined in gestation crate.
PIGS FOR MEAT
GRAPHIC IMAGES. A Compassion Over Killing investigator worked
inside a USDA-inspected slaughterhouse that supplies pig meat.