LC (Library of Congress) Subject Headings are helpful for finding books and other materials included in most academic library catalogs. These headings are assigned by catalogers who actually look at the materials and identify the subject matter of the items.
Learning to use subject heading links will produce more precise results than keyword searches. One might start a search with key words, such as humane and meat, and get a few hits. Then peruse the records of relevant items to identify specific LC subject heading links. A few examples:
Food--Moral and ethical aspects
Food industry ethics
Food of animal origin
Meat industry and trade
A few additional animal studies-related concepts:
Animal rights movement
Slaughtering and Slaughter Houses --Law and legislation
Animal Studies is covered in many academic disciplines (e.g., classics, English, history, international studies, philosophy, law, public policy, etc.). You will find books related to animal studies throughout the UW Libraries. Use the UW Libraries Search to find books related to your research topic.