What methods did employers use against unions?

Business owners hired armed guards and several battles were actually fought between workers and hired thugs. (coal miners, etc ) Employers threatened employees with loss of their jobs, their homes (since in many cases the company owned the homes), loss of their ability to work for any other company due to collusion between the companies. The companies tried to keep the union organizers out of their businesses and penalize those workers who talk to their fellow workers about a union. The business owners threaten to hire permanent replacements if they strike or walk out or participate in union organizing activities.