There's nothing wrong with keeping macaws -- which are species, NOT breeds -- as pets. Of course, this is as long as one can keep them happy and healthy -- and doing that is far more difficult than keeping a flock of chickens. I've gotten rather cranky about seeing these "how do I buy and hatch parrot eggs?" posts because they're typically written by people who think having success with chicken eggs means they can raise any bird from the egg. If that was true, then macaws and chickens would cost the same to buy -- and the OP on that thread wouldn't be looking with dollar signs in her eyes at the idea of buying fertile macaw eggs.
someone selling macaw eggs sounds like a scam to me their eggs to my knowledge are a lot more fragile then a chickens egg and it doesn't take long for them to die in the egg if they aren't in the correct conditions