Do not engage with hostile individuals. Understand that there will always be a uninformed people out there and people that might disagree with you altogether.
The best practice is to ignore them, and tell your volunteers to do the same before the protest starts. If someone yells a profanity or tries to elicit a response, always take the high road. Your disposition reflects not only on you, but on your cause, as well as activists everywhere. We have been contacted by circus goers after the protest via email, and they commented on how polite and professional we were, and how after doing some research they decided that they would not be returning to the circus again.
You are there to educate and inform. We encourage thoughtful conversations. You can change hearts and minds by telling the truth!
Should someone start harassing you, call law enforcement right away.