It is a synonym of hoe.
It is a way to call a slutty,
nappy, hot, bitchy, or
whatever kind of girl you really want a hoe with out directly saying it.
Also, to further emphasize calling her a crow, you can begin to crow at her
like a crow using a high pitched "RAAAAA, RAAAA" noise. As note, it is best to crow at them when they are passing by.