The 35-day life of a KFC chicken... in a shed full of 34,000 others: Inside farm that houses some of fast food chain's 23 million birds

1,000 farms supply fast food chain KFC with 23 million chickens a year 

Birds live in huge sheds for just 35 days before they are gassed to death

Documentary filmed around 34,000 chickens in a shed with few windows 

Activists say the conditions the chickens are kept in are 'oppressive'  

One farmer claims the birds have a short but 'very good life' 

KFC said all their suppliers meet or exceed UK and EU welfare requirements