Green’s Dictionary of Slang

a crack addict, spec. a feamle who exchanges (oral) sex for free drugs.

2000		W. Shaw Westsiders 180: She’s a chickenhead — a crack addict.
2008		in J. Miller Getting Played 129: ‘That’s what you would call something like a hoodrat, or a project chick [...] You know, a chickenhead or something. Girls that just like gettin’ dogged out’.