Who would poison peacocks? Why?

It seems peacocks were found dead and appeared to have been poisoned. How and why would this happen? Can anyone explain if they know ? How to stop this and protect birds and animals from such terrible fates? What crime did the poor birds and animals commit to suffer such a horrible death? They go about their lives peacefully. Humans are harming them under some pretexxt. How can we stop this from happening ever again? Please help if you know the answer and spread it among everyone..