2. When a Mexican is crossing through the border, they constantly yell out "Para Aca", which in spanish means "this way". When yelled in the shortend slang way in spanish as "Pa Ka" it sounds like a chicken crying out "Paa Kaaa!!" Thus why they are called Pollo's.
3. A term used to describe a Fresh Over the Border FOB Mexican. These people are usually very dark and wearing old clothes from about 10 years ago. Such as old faded Super Bowl shirts and caps from the 90's.
Dan: Yeah, that guy must be a pollo, probably has no car insurance too.