A man has been arrested following the discovery of about 1,600 dead pigs at a farm in Harewood.
The 52-year-old was questioned on suspicion of causing unnecessary suffering to animals before being released on bail pending further enquiries.
It comes after the pigs were found in varying states of decomposition at a farm on Harewood Avenue, Harewood, on November 12.
Leeds City Council’s environmental health officers are investigating suggestions the animals starved to death.
Other pigs are thought to have been found living among the dead.
Conservative councillor for the area, Rachael Procter, said residents had been left shocked by the news.
She said: “This is really alarming news and the residents of Harewood are rightly concerned about this tragic development.
“I am glad to see that a thorough investigation is now being carried out by the council and Environment Agency. My constituents will wonder how this very sad incident came about.
“If this is a case of animal neglect it is simply unacceptable. My constituents are quite rightly demanding some answers on this and the council needs to ensure this does not happen again.”
Police were called shortly before 9pm on November 12 after concerns were raised for the welfare of a man at he farm.
A West Yorkshire Police spokesman said: “Officers attended the premises in Harewood Avenue and found a large number of dead pigs.
“A 52-year-old man was arrested on suspicion of causing unnecessary suffering to animals and subsequently released on police bail pending further enquiries.
“Officers liaised with the RSPCA and with Leeds City Council Environmental Health, which is now leading the investigation.”
A Leeds City Council spokeswoman added: “Our environmental health officers are working with the Animal and Plant Health Agency and the police and as the investigation is ongoing we are unable to comment further at this time.”
A spokeswoman for the RSPCA said the charity had been contacted by police and added: “We liaised with them and the relevant Trading Standards department, who, as is RSPCA policy on investigations involving farm animals on commercial premises, were invited to, and have, taken over the investigation.”