Cattle is also fed with animal fat and flesh, not only corn. That's where the mad cow disease comes from. And the living conditions are also really bad. Chicken

Cattle is also fed with animal fat and flesh, not only corn. That's where the mad cow disease comes from. And the living conditions are also really bad. Chicken is stacked up high in boxes so small that they can't move, so it isn't a wonder that the aviary flu happened, given the high density of such operations. Industrial farms are basically subsidized with our health. But back to your point, in nature being healthy is the norm, not the exception. Any operation where cattle is getting sick regularly should be shut down, sickness being the most valuable signal you can ask for.