Why did the Sheriff need volunteers?

Ok, it was probably a small county with a small Sheriff's Dept. But the sheriff had a least 4 deputies, 3 in the courtroom scene and 1 at the Halloween party. All the sheriff had to do was go to the Ritter farm, just like Otis and his buddies did. 5 men should have been enough to handle the situation without the need for volunteers. Even if Bubba decided to flee instead of going home, which would have been unlikely,he probably still could have been found without the need to deputize any of the citizens of the town.