Eight peacocks have been found dead near a field in the Lalau village in the Agra district.
Preliminary investigations indicate that pesticides, sprayed by farmers in the field, could be the cause of peacock deaths.
Officials said consumption of such pesticide-laden grain by animals continuously for a few days could be a cause of the death.
Diwakar Srivastava, divisional forest officer (DFO), National Chambal Sanctuary, said that the carcasses of the peacocks have been sent for post-mortem to ascertain their cause of death to the Indian Veterinary Research Institute in Bareilly.
The report is yet to be received.
Meanwhile, unidentified people have been booked under various sections of the Wildlife Protection Act for peacock deaths.
(With IANS inputs)