The birds are stunned with electricity before processing. Workers work quickly and often cut themselves and others. Motions are fast and repetitive. Poultry processing ranks 3rd for cumulative trauma injuries such as carpal tunnel syndrome. There is no control over the fast pace of work.
Cold temperatures add to the risks.
The noise is overwhelming. Going to the bathroom requires permission. Un excused absence from the line is grounds for dismissal. Employers define it as a voluntary quit. For some it is easier to pee in their pants.