Thats sick.
My husband grew on a farm. I've worked with him on the farm.
Sick animals are put down, not left. If an animal is down but not sick they try to get them on their feet, the quicker after laying down the better the chance of saving the animal, after so long they are put down. Usually by a vet. They only animals I've ever heard of being drug were dead ones, it's the only way to move them into a more convenient place for the dead wagon to come and get them.
Farmers frequently slaughter for meat animals who were too injured to survive, we had some for supper, a bull gored another bull nearly to death, he had to be put down. But not sick ones. The meat is for family consumption, not market.
We haven't seen anything like what was described, but I'm sure it happens, somewhere, just not locally.
I agree with Tom, a true farmer does not do this.