A Guatemalan man who was shot in the foot crossing the U.S. border from Mexico turned up seeking treatment at a Framingham emergency room Monday. A spokesman for the U.S. Immigration and Customs Enforcement said the man could be a victim of smuggler vs. smuggler violence. ``As far as cross-border violence, it's something we're concerned about,'' said spokesman Marc Raimondi. ``Since 9/11, we've clamped down on the border, but that has made the competition among the coyotes greater.'' ``Coyotes'' are those who smuggle illegal immigrants over the Mexican border, Raimondi said. The illegal immigrants are known as ``chickens,'' he said....