Nearly 300 peacocks were on Tuesday found dead in Banodia village in Rajasthan's Ajmer district, official sources said.
The birds apparently died after consuming poisonous feed allegedly thrown by hunters, they said in Ajmer.
Villagers had reported three unidentified persons, one of them carrying a gun, who were seen feeding the birds on Thursday.
Authorities have collected samples of the grain and launched an investigation into the incident.
No arrests had been made in the case so far, police said.