Sentry boxes, called pigeon-roosts, stood every 100 feet along the top of the stockade, where guards were ordered to shoot any prisoner who crossed the deadline but otherwise had little control over conditions inside. Perched above the camp, the guards endured tedium and anxiety, fearing prisoner uprising or Union cavalry attack, and over time the noise, stench, and sight of acres of ragged men and shelters numbed the senses. They also suffered many of the same health problems as the prisoners, producing a high death rate among them as well. Most of these guards were old men and young boys from the Georgia Reserve Corps, reluctant witnesses to the misery at Andersonville while more seasoned troops were sent to stop Sherman's drive toward Atlanta. Local townspeople sometimes came to stare at the prisoners.