The protest took place on the Lewisburg town square.
Along with animal rights group activists, 13 empty collars represented each of the dogs killed last week.
"Over 6,000 people have joined us in demanding answers from Lewisburg as to why they continually choose to euthanize dogs in their care instead of adopting them out," Van Zant said. "[And it happened] in times when there is a rescue en route to save them."
Van Zant told Nashville's News 2 he and other supporters are hoping to get answers and pressure the city to change its practices and work with the more than willing and able volunteers.
Last fall, every dog in the Lewisburg Animal Shelter was killed, even though 18 of the dogs had commitments from rescuers.
The first dog rescued by Van Zant's organization had come from Lewisburg Animal Shelter, and he said he has maintained close ties to the community.