The Animal welfare Act (1966, last amended 2008) requires that minimum standards of care and treatment be provided for certain animals bred for commercial sale, used in research, transported commercially, or exhibited to the public.

The Animal and Plant Health Inspection Service (APHIS) of the US Department of Agriculture (USDA) enforces the act by inspecting laboratories and monitoring compliance with the act.

However, the act does not cover rats, mice and birds. These species are protected under the Public Health Service Policy on Humane Care and Use of Laboratory Animals, which is based on the Health Research Extension Act (1985). However, PHS Policy applies only to those research facilities receiving federal funding by National Institute of Health (NIH). Scientists must comply with guidelines set forth in the Guide for the Care and Use of Laboratory Animals (eight edition, 2011) from ILAR.