Thorleif Schjelderup-Ebbe

Thorleif Schjelderup-Ebbe (12 November 1894 in Kristiania – 8 June 1976 in Oslo) was a Norwegian zoologist and comparative psychologist. He was the first person to describe a pecking order of hens, a discovery that contributed to understanding dominance hierarchies across species and influenced the field of ethology. Provided by Wikipedia