When was Vultures by Chinua Achebe written?

There is not a definite date, however, it is most likely to be just after 1967 when lots of ethnic violence in Nigeria lead to a civil war, this is symbolised a lot throughout the poem!

Actually, at the 30th line, he references "Belsen" which was a concentration camp in Germany in 1943.

I believe that he has based this poem on WWII, so the poem had to have been written around there.