Thanks for the concerning news Kariuki.
One would hope non-lethal methods such as hiring falconers to frighten away rice-eating birds would be tried before lethal options like poison, etc. are used.
But based on this article from 2013, where Quelea were sprayed from the air, this may not be the case:
One wonders which poison is used, how much does it bio-accumulate up the food chain, where and when are they spraying the Quelea (breeding colonies or in the ricefields themselves), and more.
Good birding,
Nate