I agree with the other people on the thread. I have had dogs in my birds. First, you talk to the owners, if you know who they are, and ask them to keep their dogs confined. I don't know about where you live, but most areas DO have a leash law.
If they don't, you then call animal control, who will help you trap them. At least here they do. And then they go to the shelter.
And if that does not stop the problem, you have your Guineas to help you be alert to dogs, and you shoot the marauding dogs. I use a small 22 calibre revolver because I can deal with the recoil, and I have small shotgun shells because they have a wider spread.
I guess you need to check the laws, the state police will know, but here, it is indeed legal to shoot a dog who is bothering livestock.
I love dogs, I have five of my own, but I keep them in our yard. We all have not only a right to protect our birds, but also a responsibility, because chickens are really pretty helpless against predators.
And yes, get a Peacock to go with the Guineas! You will have to protect it against the Guineas until it is full grown, but then it will do very well for itself! Get two, a male and a female! You will LOVE them.