Oregon Revised Statutes Animals § 609.150

(1) Except as provided in subsection (3) of this section, any dog, whether licensed or not, which, while off the premises owned or under control of its owner, kills, wounds, or injures any livestock not belonging to the master of such dog, is a public nuisance and may be killed immediately by any person. However, nothing in this section applies to any dog acting under the direction of its master, or the agents or employees of such master.

(2) If any dog, not under the control of its owner or keeper, is found chasing or feeding upon the warm carcass of livestock not the property of such owner or keeper it shall be deemed, prima facie, as engaged in killing, wounding or injuring livestock.

(3) No person shall kill any dog for killing, wounding, injuring or chasing chickens upon a public place, highway or within the corporate limits of any city.