http://www.dailymail.co.uk/news/arti...-chlorine.html

Just one quote:
"Unlike in the UK and Europe, there are no minimum space requirements
for breeding chickens in the US. America also does not have any rules
governing lighting levels in the sheds and, crucially, its farms have
no maximum allowed level of ammonia, which indicates how much urine
and faecal matter is present. This means there is no limit on how much
can fester inside the sheds."

I bet those are the famous Costco rotisserie chickens.