Animal treatments are limited. There is no therapeutic insistence on avoiding fatal outcomes for an individual. Similarly, there is no treatment of immuno-deficient animals with the aim to keep them alive at all costs. The animal is simply sacrificed. Furthermore, animals treated with antibiotics live only a short period of time.
Husbandry methods allow for entire flocks to be slaughtered simply to clean the stables.
This stock turnover has helped us to reduce the development of resistance in animals. Incidentally, pigs grow from one kilogram to 100 kilograms over this period. The issue of salmonella in broilers and turkeys represents an interesting test case. In one recent study, hatching eggs were placed in an incubator. The very next day, the chicks were already threatened by salmonella infection.