One study, however, suggests that many unfit birds escape the net and get into our shops. The first sample consisted of 90 chickens and chicken portions which were examined by a poultry expert from the Royal College of Veterinary Surgeons. He judged 32 of the 90 birds to be 'unfit for human consumption' as defined in the poultry meat regulations. Which found half the birds to be contaminated with either salmonella or campylobacter. From the human viewpoint, we can hardly expect to get healthy food from unhealthy animals.
Antibiotics are, in effect, being used as a substitute for good husbandry and hygiene.
In theory one may distinguish between those antibiotics which are used for growth promotion and those used for prophylactic purposes. In practice the distinction is blurred as antibiotics used as growth promoters also help prevent disease. What is clear is that, without the routine use of antibiotics, factory farming could not survive as infectious disease would overwhelm many intensive livestock units. The World Health Organisation has stressed that resistant strains of four bacteria which cause disease in humans have now been transmitted from animals to people. These are salmonella, campylobacter, enterococci and E.coli 0157.