Chicken Shack are a British blues band, founded in the mid-1960s by Stan Webb (guitar and vocals), Andy Silvester (bass guitar), and Alan Morley (drums), who were later joined by Christine Perfect (later McVie) (vocals and keyboards) in 1967. Chicken Shack has performed with various line-ups, Stan Webb being the only constant member.

Source: Wikipedia (https://en.wikipedia.org/wiki/Chicken_Shack)