If a bite of food falls on the ground, often we pick it up and eat it. Five second rule, right? But if it falls in something gross or we haven't cleaned the floor in awhile, we don't eat it. Because that's gross. Especially if your floor is covered in chicken shit.
It's unclear, then, why we are okay with eating chickens that have been transported in crates that are never, ever cleaned. Never. By 80 percent of poultry growers, at least. Which means that there's a 4 in 5 chance that your chicken dinner was rolling around in something far nastier than a little floor dust.