It was in reference to George Burdock, 70, who allegedly shot Lilly, a husky mix, in the eye while walking his dogs Thursday.
Lilly lost her eye in the shooting.
Chris Murphy, an animal activist, helped organize the Sunday's protest using Facebook.
"This is not south central Chicago, you know, why do you feel you have to be armed? And why do you feel you have to shoot a dog in the face?” said Murphy.
Lilly’s veterinarian, who was also walking in protest, said he has never seen the dog be aggressive in the time he has known her.
“Even if there was a growl or anything like that, which I am not aware of that happening, that happens all the time in dog parks and on sidewalks every day. People just don’t pull out guns and shoot dogs because they are doing dog behavior,” said Randall Cannon.
Morgan Frazier, whose brother witnessed the shooting, told police the dog was acting aggressively.
“I could see if he thought his dogs’ lives were in danger, but I don’t know if shooting the dog was the right thing. But the dog should have been on a leash and it probably wouldn’t have happened,” he said.
Burdock placed several no trespassing signs in his yard since the incident.
Lilly is recovering at home.