They complained of high euthanasia rates, cramped and uncomfortable quarters and a lack of capacity at the shelter, which opened in the 1980s with about 50 kennels and has since expanded to about 90.
Still, the activists argued that that is a subpar capacity level for the number of stray dogs and cats collected by county animal control officers, most of which are euthanized.
"I had no idea that 60 to 80 percent of animals are being euthanized at our public shelter," said Janet McAfee of Upland.
While she commended animal control officials for their best efforts in properly confining and caring for the animals, she said more should be done.
Christine Haslet, an animal rights activist from San Diego, said she was disturbed by the number of dogs and pets that are spayed and neutered for pet fairs, only to return to the animal shelter for euthanasia if they are not adopted.
"This is wrong on so many levels. These are God's creatures you are destroying," Haslet said.
While the Devore shelter does in fact wind up euthanizing about two-thirds of the animals it houses, the number of dogs and cats it adopts out are in line with that of other shelters in the county, said Brian Cronin, division chief for county Animal Care and Control.
Cronin attributes an increase in adoptions partly to the animal rights activists, who have drawn attention to the Devore shelter.
County animal shelters, including Devore, hold stray animals 96 hours before euthanizing them when state law only requires they be held for 72 hours.
The county also continues to fund a spay/neuter voucher program for residents, Cronin said.
He said volunteers are welcome to participate in the pet adoption fairs hosted by animal control officials, but the Devore shelter, where daily euthanizations are a grim reality, is not an environment conducive to animal rights activists.