The surname of CHICKEN was of two fold origin, it was an ancient baptismal name meaning 'the son of Chick', originally derived from the Old English word CICEN.
It was also of the occupational group of surnames for someone who bred poultry for the table.
Many modern family names throughout Europe reflect the profession or occupation of their forbears in the Middle Ages and derive from the position held by their ancestors in the village, noble household or religious community in which they lived and worked.
The addition of their profession to their birth name made it easier to identity individual tradesmen and craftsmen.
As generations passed and families moved around, so the original identifying names developed into the corrupted but simpler versions that we recognise today.