I used to work in a city next to Vernon (the city mentioned in the article that has a rendering plant) that I had to drive by everyday. OMGoodness, I had to roll up my windows & close the vents in my car bc it stunk to high heaven.

There was also Farmer John plant & I saw pigs in trucks going to be made into sausages (I don't eat pork & red meat, rarely eat chicken now) & when I drive home in the evening, yucky oily residue got on my car.
Linking this so you can take a look @ the rendering plant's White Paper.
Dead Dogs and Cats Use to Make Meat Meal
Just avoid pet foods w/ 'mystery' meat, flavorings & oils (e.g. 'Meat & Bone Meal', 'Natural Flavors', 'Poultry Fat', 'Fish Oil' etc.). It can come from 4'D meat, the Dead, Dying, Diseased & Disabled & rendered from euthanized animals, even dogs & cats. But it's also used in fertilizer & poultry feed (Exactly why I'm trying to stop eating chicken, I don't even think organic is safe anymore! Guessing cage free is ok?), which ultimately lands on our dish.