All the raw materials of KFC chain fast food with foreign flavor are purchased from China, and the largest chicken supplier is also from China. KFC is very strict with its suppliers. As a fast food chain, KFC requires the specifications of chicken products to be quite different from the export raw materials produced by most enterprises at that time, especially in terms of the weight of chickens. Normal chickens need to be raised for about 52 days before they can be slaughtered, while KFC products require the chicken source to be about 42 days. AA+ broiler is a high-quality broiler variety commonly used by catering giants such as KFC and McDonald's. Entering KFC and other high-end industrial chains requires higher requirements, and the most important thing is to pay attention to biosafety and drug residues. Biosafety means that chickens can't get sick, and drug residue means reducing the dosage of antibiotics, so that the residual drugs in chickens meet international standards. Therefore, all personnel entering the chicken house must go through a series of disinfection measures to avoid bringing possible viruses into the chicken house. At the same time, if safety measures are kept up, the use of antibiotics can be reduced by about 21%, and drug residues can be avoided. In order to prevent the introduction of external germs, chicken farm employees are generally not allowed to leave the chicken farm during the three months from the introduction of chicken seedlings to the slaughter of adult chickens.