Maryland has several months of hard freeze during the winter months.Feral cat populations will be semi-controlled by nature.
Mississippi does not have the same weather cycles as Maryland.
What works in Maryland does not work at all in Mississippi.
When I was a teenager in NY state, I went to an auto junk yard looking for some parts and I remember 3 different cars in there that had long since dead cats impaled with engine fans and crushed in the fan belts. Cats would fall asleep on the warm engine blocks and the owner would start the engine later.