KFC responded by saying the chickens used in its products are bought from suppliers like Perdue Farms, Tyson Foods, and Pilgrim's Pride, and that these suppliers are routinely monitored for animal welfare violations. Several PETA undercover investigations and videos of these and other KFC suppliers purport to show chickens being beaten, ripped apart, and thrown against walls contradict KFC’s claims. PETA has criticised some of the practices of chicken breeders, such as beak trimming and overcrowding, but KFC says its suppliers meets UK legal requirements. The Department for Environment, Food and Rural Affairs recommends a maximum stocking density of 34 kg—around 30 chickens—per square metre, and say that in circumstances where beak trimming needs to be carried out to prevent the birds injuring each other, only one third of the beak should be trimmed "measured from the tip towards the entrance of the nostrils". PETA states that they have held more than 12,000 demonstrations at KFC outlets since 2003 because of this alleged mistreatment of chickens by KFC suppliers.