A decision not to lay animal cruelty charges in connection with the deaths of guinea pigs at a zoo in New Brunswick has prompted outrage.

About two dozen protesters showed up at the Cherry Brook Zoo in Saint John on Sunday to voice their displeasure.

The New Brunswick SPCA said last week that it recommended laying criminal and other charges for inhumane euthanasia and causing unnecessary pain and suffering to animals, but the Crown decided not to proceed with a prosecution.

It is not clear how many guinea pigs died at the zoo or under what circumstances their deaths occurred. The SPCA’s investigation began in January.

Zoo executive director Martha McDevitt told CTV Atlantic that animals euthanized for feed at the zoo are treated as humanely as possible.

“I know what standards we follow and I know that there’s no suffering with any of the animals,” she said.

Canada’s Accredited Zoos and Aquariums lists Cherry Brook Zoo as one of its two accredited facilities in New Brunswick. It has launched its own investigation into the guinea pigs’ deaths.