好奇研究了一下FDA的网站

从他家网站搜出来，FDA是不管鸡的。管鸡的是农业部的另外一个机构FSIS。

https://www.foodsafety.gov/about

Selected Federal Agencies with a Role in Food Safety

The Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture, the U.S. Food and Drug Administration (FDA), and the Centers for Disease Control and Prevention (CDC) serve important roles in ensuring food safety in the United States.

• Food Safety and Inspection Service: FSIS is the public health agency in the U.S. Department of Agriculture responsible for ensuring that the nation's commercial supply of meat, poultry, and processed egg products is safe, wholesome, and correctly labeled and packaged.
• U.S. Food and Drug Administration: The FDA is charged with protecting the public health by assuring that foods (except for meat from livestock, poultry and some egg products which are regulated by FSIS) are safe, wholesome, sanitary and properly labeled; that cosmetics and dietary supplements are safe and properly labeled; that human and veterinary drugs, and vaccines and other biological products and medical devices intended for human use are safe and effective; regulating tobacco products; and protecting the public from electronic radiation
• Centers for Disease Control and Prevention: CDC leads federal efforts to gather data on foodborne illnesses, investigate foodborne illnesses and outbreaks, and monitor the effectiveness of prevention and control efforts in reducing foodborne illnesses. CDC also plays a key role in building state and local health department epidemiology, laboratory, and environmental health capacity to support foodborne disease surveillance and outbreak response.

然后又从FSIS的网站找到了让不让用抗生素的文件。答案是：

Antibiotics may be used to prevent disease and increase feed efficiency. Before the bird can be slaughtered, a “withdrawal” period is required from the time antibiotics are administered. This ensures that no residues are present in the bird’s system. FSIS randomly samples poultry at slaughter and tests for residues. Data from this monitoring program have shown a very low percentage of residue violations.