Which delicacy is banned in most parts of Europe and the United States due to ethical concerns

Foie Gras, I think.

Foie Gras is a controversial food where birds are force fed, but for the most part well cared for.

foie gras or fatty liver.

Explanation:

Foie gras is a French delicacy which is actually a fatty liver of a duck or a goose. this fattened liver is forcefully fed to birds for producing the fatty consistency. The birds are given fatty liver with boiled corn to facilitate ingestion and to make them eat more than their capacity. the foie gras is banned in most parts of Europe and United States because it is unethical and violation of animal rights. The birds have difficulty in walking, breathing and high liver fat deposition may cause death of birds.