A Yardbird isn't a chicken. From Wickipedia:
1 : a soldier assigned to a menial task or restricted to a limited area as a disciplinary measure
2 : an untrained or inept enlisted man
Charlie Parker (the sax Charlie, not the banjo one) was nicknamed "Yardbird," though I don't recall why.
And "Chickasay" is "Chickasaw" (an Indian tribe) in local dialect.
That is all.