Selecting generation after generation of birds for their faster growth rates and higher meat yields has left the birds’ immune systems less able to cope with infections and there is a high degree of genetic uniformity in the population, making spread of the virus all the more easy. Further intensification of the industry has been suggested by some as the solution to avian flu, on the rationale that keeping birds indoors will prevent contamination. However, this relies on perfect, fail-safe biosecurity – and such measures are near impossible to implement. Movement between farms of people, materials.
