became more popular still with the founding of People for the Ethical Treatment of Animals (PETA) in 1980 and PETA's years-long legal battle over the Silver Spring monkeys, 17 research macaques found to be living in welfare-compromised conditions in an undercover investigation by PETA's Alex Pacheco. Laws Federal The 1958 HMSA was the first major federal law concerning animal welfare. The HMSA stipulates that animals be "rendered insensible to pain...before being shackled, hoisted, thrown, cast, or cut", and sets out which methods of slaughter are appropriate for which species. The enforcement of the HMSA is questionable. The law lacks a general enforcement mechanism - its original enforcement mechanism, the prohibition of federal purchases of animal products whose slaughter violated the HMSA, was repealed in 1978. In 2010 the Government Accountability Office (GAO) released a report criticizing the United States Department of Agriculture's (USDA) enforcement of the HMSA. Chickens, which account for over 95% of farm animals slaughtered in the U.S., are exempt from protection under the HMSA. The basis of animal welfare legislation in the US is the Animal Welfare Act of 1966 (AWA). The original AWA was aimed at regulating the sale and transport of animals. The AWA is enforced by the USDA, APHIS, and the Animal Care agency. Federal animal care standards mainly cover humane handling, housing, space, feeding, sanitation, shelter from extremes of weather, adequate veterinary care, transportation, and handling in transit. The AWA was amended eight times, in 1970, 1976, 1985, 1990, 2002, 2007, 2008, and 2013. In 1970, the Act was amended (Pub.L. 91–579) to include all warm-blooded animals used in testing, experimentation, exhibition, as pets or sold as pets. Certain cases could be exempted from such definitions unless they used live animals in substantial numbers. Fines were increased for those interfering with an investigation of an experimentation facility. Those found guilty of assaulting or killing Federal inspectors responsible for such tasks also faced additional sentencing. Basic treatment was expanded to include humane and reasonable handling of the animals, and required shelter from weather and temperature extremes, proper ventilation, adequate housing, decent sanitation, and adequate veterinary care at all stages in the animal's life. The Act was further amended in 1976 (Pub.L. 94–279) to further regulate animal treatment during transportation. Animals were to be kept in adequately sized traveling accommodations, and to be kept from fighting amongst one another. The definition of animal was broadened