Collective bargaining for lawful purposes is legal. No person shall be indicted, prosecuted or tried in any court of this state for entering into or carrying on any arrangement, agreement or combination between themselves made with a view of lessening the number of hours of labor or increasing wages, bettering the conditions of working men and women or for any act done in pursuance thereof, unless such act is in itself forbidden by law if done by a single individual

ORS 661.030 — under Chapter 661.