Try for audience participation: raise your hand if you have a dog, then keep your hand raised if your dog came from a pet store. Then ask one or two of those with their hands still raised if they know where their pet store dog actually came from. It will be bit controversial, because you are making it personal, but it may hit home for those who have not yet purchased a dog from a store.
Good luck!
This just popped into my head. That old song" how much is that doggie in the window?" How much indeed? Because puppy mill dogs are so unhealthy & full of disease you end up paying a ton of vet bills. That's all I got. PS good topic!
PSS Joe here just got himself reported!