The Crowbar is a melee weapon which a player may find occasionally inside normal buildings and as such is treated as a Primary weapon. Its damage is comparable to that of the hatchet.
The crowbar is also the quietest non-suppressed weapon in the game. The Crowbar is also the heaviest melee weapon you can use in vanilla DayZ, if you wish for your movement to stay quick its suggested you drop this for an Axe or Machete.
In update 1.7 the Baseball bat and Crowbar will be able to knock a player out with a hit to the head.