With over 70 billion chickens raised for meat globally each year, broiler chicken welfare represents the largest scale animal welfare issue in modern animal agriculture, with systemic problems driven by selective breeding.
The scale of broiler chicken welfare problems is almost incomprehensible. More than 70 billion individuals annually - vastly outnumbering every other farmed animal - experience chronic welfare deficits that are built into their biology. The leg disorders causing lameness in 25-30% of birds mean hundreds of millions of animals experiencing daily pain simply from walking. The cardiovascular disease killing millions from sudden death syndrome means birds dying acutely from heart failure in the middle of otherwise normal activity. The density of conventional production prevents normal social and foraging behavior in cognitively more capable birds than often appreciated. No other welfare issue affects as many individual animals simultaneously.