This is also fairly common slang among southern black folk to refer to a fairly dimwitted girl that you are likely to meet and have sex with soon afterwards. Project Pat made a song about it fairly recently, but the term is quite old. I inherited a 45 record by Bobby Rush from my uncle. The record was called Chickenheads and it dates from the early sixties. Chickenhead can really be used in roughly the same way as hood rat, but is only used when referring to women. It is quite offensive, really. I had a woman at work seriously pissed when I called her a chickenhead a number of years back, and rightly so. It was a terrible thing to call a person.