Ask police in Portland, Oregon, why the chicken crossed the road, and they have no idea.

Officers were dispatched last week to the Linnton district after a caller said a chicken was crossing a rush-hour highway, causing a traffic hazard.

In a statement titled in part "Officers Unable to Determine Chicken's Intent," the police bureau said officers were unable to locate the bird, and that animals in the roadway are no laughing matter. They also released audio of the tip-off, in which the caller assures a dispatcher that "this is actually not a prank call."

Police spokesman Sgt. Pete Simpson said officers regularly tend to duck crossings and have been known to rescue ducklings from storm drains. He said it was the first time they had received a serious call about a chicken trying to cross a road.

Officers will remain on the lookout for the bird, he said.