The dirtiest job I have had the pleasure of working would be the Maple Leaf Chicken Hatchery.
On the day shift Monday-Friday, 5am-3pm workers sort the female birds from the male birds when they are only a few hours old. The birds are hatched in trays then fed into the egg separating machine, then the birds are dumped onto a conveyor belt for sorting. Sometimes rotten eggs would dump onto the conveyor, birds with their insides hanging outside their bodies, birds with 4 legs or beaks that will never open.
The birds that were no good were sent to the shredder where they would be chopped into pulp. While sorting the birds, you flick them into shoots, sometimes employees get poop in their eye or mouth.
The night shift would power wash the egg separating machine where birds that got stuck in the gears would be sprayed out. Some birds would be stuck in the machine alive but would have to be flooded out of the machine with the pressure washer. Pressure washing results in dirty water splash back in your face and mouth.
Then there was the egg room....but you should visit to find out more.