@AfterSchoolWorry
The explanation given for meat plants here in Ireland has 'oh they are all non-nationals who tend to share accommodation' , but then why not fruit pickers, other food industries?
What is it about meat processing plants?
Meat and poultry processors are working indoors, in close proximity, in noisy, cold and moist conditions (though actually there were outbreaks on fruit farms in the summer, shared accommodation likely to be a factor). Dozens of food plants have had outbreaks, from abattoirs, meat and poultry cutting and packing plants, sandwich and ready meal factories.
Whatever the conditions inside the plant, whatever 'rules' are set out by management or, indeed, government, a common factor is that they are largely staffed by migrant workers, either seasonal or long-term migrants. Often a large number of men (usually) will share staff accommodation, grubby caravans or houses, or they will rent privately, and to keep their costs to a minimum there are houses of overcrowded multiple occupation where they sleep several people to a room, even hot-bedding so the night shift worker goes to sleep for the day in a bed vacated by one going to work in the morning. Hygiene is an alien concept AT work, let alone out of work, and social distancing absolutely won't happen. Whilst of course these standards are not universal, large groups living in an overcrowded house, who then work together all day or night in a cool, moist food plant, are ideal for any virus to spread.