Some United States sheep breeders dedicated to breeds from the United Kingdom are concerned about shrinking gene pools. Throughout American history, British settlers introduced breeds such as Lincoln, Leicester Longwool, Shropshire, Suffolk, and Hampshire. More recently, some U.S. sheep breeds have morphed into anatomically larger versions of their British counterparts, arguably leading to a decline in meat and overall carcass quality. The average weight of a U.S. lamb carcass in 1980 was 55
