Why millions of poultry birds culled during the epidemic of Bird flu?

Question

It is necessary to destoy the virus as it is communicable to man.Is there other way, instead of culling poultry.

Answer 1

how does one know which particular bird is infected among the huge nos of birds kept at a partcular poultry farm...also if smthg is not done immediately the virus can spread to humans preety fast...vacinations which are available im sure wud cost more both in terms of money n time..so culling is the only easy n fast way of containing the virus..

Answer 2

If poultry birds are not culled during epidemic, all the consumers of the epidemic affected will have to be culled.  It is easy to cull birds than ?