If you had an attack then the predators were around already. Why they didn't bother you before that I couldn't say. I hope you didn't suffer any losses to your flock.
Possibly could attract some attention, the sound may induce them come to check out what's making the noise. If you have a predator that has successfully hunted chickens before and associates the sound with a meal then certainly like a dinner bell but for one that hasn't then it would be more...